Questions on Algebra: Probability and statistics answered by real tutors!

Tutors Answer Your Questions about Probability-and-statistics (FREE)

Question 308006: How do you find the 30th and 90th percentiles?
129, 113, 200, 100, 105, 132, 100, 176, 146, 152

a* 30th percentile = 105
90th percentile = 200
b* 30th percentile = 113
90th percentile = 200
c* 30th percentile = 105
90th percentile = 176
d* 30th percentile = 113
90th percentile = 176
Thanks!
Click here to see answer by rfer(12726)

Question 307930: The letters G E O M E T R Y are written on a set of cards. You mix
the cards thoroughly.Without looking, you draw one letter, replace it,
then draw another. Find each probability.
P(E, T)
&
P(M, Y)
Click here to see answer by Fombitz(13828)

Question 307916: You work at a T-shirt printing business. 564 of 4,700 T-shirts shipped
are printed improperly.
Predict the number of improperly printed T-shirts in a batch of
2,000.
Click here to see answer by checkley77(12569)

Question 307905: The scores on an exam are normally distributed, with a mean of 77 and a standard deviation of 10. What percent of the scores are greater than 87?
* 68%
* 16%
* 84%
* 2.5%
Click here to see answer by scott8148(6628)

Question 307904: The numbers of cookies in a shipment of bags are normally distributed, with a mean of 64 and a standard deviation of 4. What percent of bags of cookies will contain between 60 and 68 cookies?
* 50%
* 13.5%
* 68%
* 34%
Click here to see answer by scott8148(6628)

Question 307906: A grocery store will only accept yellow onions that are at least 3 in. in diameter. A grower has a crop of onions with diameters that are normally distributed, with a mean diameter of 3.25 in. and a standard deviation of 0.25 in. What percent of the onions will be accepted by the grocery store?
* 34%
* 97.5%
* 84%
* 50%
Click here to see answer by scott8148(6628)

Question 308028: in a class of 24 students 19 take social studies, 22 take math and all take either social studies or math.
How many students take both social studies and math
A student from the class is selected at random.
Find
1.The probability that he stakes social studies
2. The probability he takes math
3. The probability he takes both math and social studies
Click here to see answer by scott8148(6628)

Question 308151: "A true-false test contains 10 questions. In how many ways can a student answer the questions if some questions may be left unanswered?"
I know that the number of answer combinations when answering each question is 2^10 = 1,024. I just am not sure how to incorporate the student not answering some. And I'm assuming that there is a possibility that the student will not answer any? The question is written exactly how I typed it. Thank you in advance!
Click here to see answer by scott8148(6628)

Question 308180: A baseball team has 15 players on it's roster. How many ways are there to pick nine starters?
Click here to see answer by nyc_function(2733)

Question 308180: A baseball team has 15 players on it's roster. How many ways are there to pick nine starters?
Click here to see answer by edjones(7569)

Question 308188: in a ten question multiple-choice test with 4 choices for each question, a student who is not prepared guesses on each item. find the probability that they get 6 correct
Click here to see answer by edjones(7569)

Question 308256: Please can someone help explain how to do this. I have tried to do this but I keep getting stuck. I keep getting numbers like 2.45E+10. I have lots of these to do and cannot figure out how to do these. Thanks.
A die is rolled 20 times and the number of twos that come up is tallied. Find the probability of getting the given result. More than three twos.
A) .564
B) .433
C) .905
D) .403
Click here to see answer by scott8148(6628)

Question 308264: Indicate which of the numbers below would qualify as measures of probability
(a) 1 (d) 0.8 (g) 150% (j) 1/4 (m) -0.5
(b) 3/5 (e) 5% (h) 0.25 (k) 1.1 (n) 0.99
(c) 75% (f) 108% (i) 2 (l) -7/8 (o) 0

Click here to see answer by nyc_function(2733)

Question 308294: Determine the probabilities of the following events occourring
1. The odds in favor of the event are 2 : 3
2. the odds against the event are 5 : 1
3. The odds in favour of the event are 100 : 1
4. The odds against the event are 4 : 3
Click here to see answer by Fombitz(13828)

Question 308498: Using correct mathematical notation and symbols, express the following in set builder notation: Z = {8, 9, 10, 11, 12, 13, 14}
Thank you

Click here to see answer by solver91311(17070)

Question 308526: The probability for heart disease in a population is 30%. The probability for the flu in the population is 50%. The probability of getting both is 10%
Click here to see answer by stanbon(57953)

Question 308569: Lisa has nine rings in her jewelry box. Five are gold and four are silver. If she randomly selects 3 rings to wear to a party, find each probality:
P(2 silver or 2 gold)
P(at least 2 gold)
Click here to see answer by stanbon(57953)

Question 308582: If the p-value is less than α in a two-tailed test, the null should be rejected
Click here to see answer by stanbon(57953)

Question 308630: Find z score that seperates the bottom 55% from the top 45%
Click here to see answer by stanbon(57953)

Question 308620: City A B C D E F G
Noon Temperature 50 33 27 t 68 44 40
F
The table above shows the noon temperatures for seven cities designated A through G. If the median noon temperature of these cities is 40oF, then the noon temperature for City D could be any of the following EXCEPT
a) 29F b) 35F c) 39F d) 40F e) 42F

Click here to see answer by stanbon(57953)

Question 308541: Find a confidence interval for u assuming that each sample is is from a normal population
a. x-bar=24,s=3,n=7,90percent
b. x-bar=42,s=6,n=18,99percent
c. x-bar=119,s=14,n=28,95percent
Click here to see answer by stanbon(57953)

Question 308614: A market research group specializes in providing assessments of the prospects of sites for new children toy stores in shopping centers. The group assesses prospects as good, fair, or poor. The records of assessments made by this group were examined, and it was found that, for all stores that had annual sales over $1,000,000, the assessments were good for 70%, fair for 20%, and poor for 10%. For all stores that turned out to be unsuccessful, the assessments were good for 20%, fair for 30%, and poor for 50%. For a randomly chosen store, what is the probability that prospects will be assessed as good?
Click here to see answer by stanbon(57953)

Question 308543: A random sample of 16 pharmacy customers showed the waiting times below (in minutes)Find a 90 percent confidence interval for u. assuming that the sample is from a normal population
21 22 22 17 21 17 23 20
20 24 9 22 16 21 22 21
Click here to see answer by stanbon(57953)

Question 308669: Construct a scatter plot using excel for the given data. Determine whether there is a positive linear correlation, negative linear correlation, or no linear correlation. Complete the table and find the correlation coefficient r. The data for x and y is shown below.
x 11 -6 8 -3 -2 1 5 -5 6 7
y -5 -3 4 1 -1 -2 0 2 3 -4
a: Scatter plot

b: Type of correlation (positive linear correlation, negative linear correlation, or no linear correlation)

Click here to see answer by Fombitz(13828)

Question 308674: I am just not understanding this and my textbook is not clicking with me. Any help would be appreciated.
For a group of 11 college football players, the mean heart rate after a morning workout session was 93 beats per minute and the standard deviation was 8. Find the 95% confidence interval of the true mean for all college football players after a workout session.
Click here to see answer by rapaljer(4667)

Question 308686: A medical reseracher wishes to determine the percentage of females who take vitamins. He wishes to be 99% confident that the estimate is within 4% of the true proportion. How large should the sample size be?
Click here to see answer by stanbon(57953)

Question 308667: A software company has 3 customer service representatives. After a week of observation a supervisor determines that there is an 85% probability that 1 customer service representative will be on the phone with a customer at any given time. What is the probability of all 3 representatives being on the phone at the same time? Round to the nearest percent if necessary.
Click here to see answer by stanbon(57953)

Question 308487: Use Chebyshev’s theorem to find what percent of the values will fall between 59 and 107 for a data set with mean of 83 and standard deviation of 8.
- Use the Empirical Rule to find what two values 67% of the data will fall between for a data set with mean 103 and standard deviation of 12.

Click here to see answer by stanbon(57953)

Question 308734: Probability question: a student is taking two courses, history and math. The probability the student will pass the history course is .6, and the probability of passing the math course is .7. The probability of passing both is .5. What is the probability of passing at least on course?
Is this the correct answer?
1-(.3)(.4)(.5)=.94
Click here to see answer by stanbon(57953)

Question 308725: students in a class took a exam. as part of an experiment to see how much of the course they remembered. they took equivalent forms of the exam in monthly intervals. the average score for the group f(t), after T months was modeled by the function.
f(t)=88-12In (t + 1), 0 a) what was average score on original exam?
b) what was average score after 4 months?
Click here to see answer by stanbon(57953)

Question 308763: You work at a T-shirt printing business. 564 of 4,700 T-shirts shipped are printed improperly. Predict the number of improperly printed T-Shirts in a batch of 2,000
Click here to see answer by stanbon(57953)

Question 308806: A race car driver tested his car for the number of seconds required to travel from 0 to 60 mph. In 20 test he obtained an average of 4.85 seconds with a standard deviation of 1.47 seconds. Construct a 95% confidence interval for the 0 to 60 time.
Click here to see answer by stanbon(57953)

Question 308881: 5.The advisor of an ecology club at a large college expects that the group consists of 10% freshman, 20% Sophomores, 40% Juniors and 30% Seniors. The membership for the club this year is observed to be 14 freshman, 19 sophomores, 51 Juniors and 16 Seniors. At 95% level of confidence, test the advisors belief.
Click here to see answer by stanbon(57953)

Question 309058: A set of data has mean 66 and standard deviation 7. Find the z-score of the value 32.
* 0.4
* 4.9
* –34
* –4.9
Click here to see answer by Fombitz(13828)

Question 309059: In a sample of 138 teenagers, 38 have never been to a live concert. Find the sample proportion for those who have never been to a live concert.
* 4%
* 28%
* 50%
* 72%
Click here to see answer by nyc_function(2733)

Question 309088: Six employees of a marketing firm had effectiveness ratings as follows: 0.72, 0.46, 0.59, 0.64, 0.81 and 0.76. Find the probability of selecting an employee with the indicated effectiveness rating.
a. Greater than 0.75.
b. Less than 0.75 but greater than 0.5.
c. Greater than the mean.

d. Not less than 0.9.

Click here to see answer by Fombitz(13828)

Question 309096: 5. In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 12 patients using the drug is selected. Find the probability that:
Click here to see answer by stanbon(57953)

Question 309114: The table shows the results of a survey of students in two math classes.
Find P(more than 1 hour of TV | 6th period class). Round to the nearest thousandth.

Did You Watch More Than One Hour of TV Last Night?

3rd Period Class: Yes- 11 No- 6
6th Period Class: Yes- 12 No- 10

* 0.647

* 0.565

* 0.435

* 0.765
Click here to see answer by stanbon(57953)

Question 309145: 6. X has a normal distribution with a mean of 70.0 and a standard deviation of 3.0. Find the following probabilities:

(A) P(x < 68.0)
(B) P(68.0 < x < 72.0)
(C) P(x>73.0)

Click here to see answer by Fombitz(13828)

Question 309161: Suppose you play a game where you flip a coin. If is heads, you lose $1.00. If it is a tail, a die is rolled. If it is an even number, you win $ 2.00. If it is an odd number, you lose $3.00. Find the expected value
Click here to see answer by stanbon(57953)

Question 309143: 5. In testing a new drug, researchers found that 5% of all patients using it will have a mild side effect. A random sample of 12 patients using the drug is selected. Find the probability that:

(A) exactly three will have this mild side effect
(B) at least two will have this mild side effect.
Click here to see answer by stanbon(57953)

Question 309136: a market analyst is hired to provide information on the type of customers who shop at a particular store. a random survey is taken of 100 shoppers at this store. of these 100, 73 are women. the shoppers are grouped in three categories, under 30, 30 and up to 50 and 50 and over. the data is summerized in the table.
let w be the event that a randomly selected shopper is a woman.
let a be the event that a randomly selected shopper is under 30.
Click here to see answer by stanbon(57953)

Question 309134: Dave the jogger runs the same route every day (about 2.2 miles). On 18 consecutive days, he recorded the number of steps using a pedometer. The results were:
3,450 3,363 3,228 3,360 3,304 3,407 3,324 3,365 3,290
3,289 3,346 3,252 3,237 3,210 3,140 3,220 3,103 3,129
(a) Construct a 95 percent confidence interval for the true mean number of steps Dave takes on his run.
(b) What sample size would be needed to obtain an error of ± 20 steps with 95 percent confidence?
(c) Using Excel, plot a line chart of the data. What does the data suggest about the pattern over time?

Click here to see answer by stanbon(57953)

Question 309133: The letters G E O M E T R Y are written on a set of cards. You mix the cards thoroughly. Without looking, you draw one letter, replace it, then draw another.
Find each probability.
1. P(E,T)
2. P(M,Y)
Click here to see answer by stanbon(57953)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800, 10801..10845, 10846..10890, 10891..10935, 10936..10980, 10981..11025, 11026..11070, 11071..11115, 11116..11160, 11161..11205, 11206..11250, 11251..11295, 11296..11340, 11341..11385, 11386..11430, 11431..11475, 11476..11520, 11521..11565, 11566..11610, 11611..11655, 11656..11700, 11701..11745, 11746..11790, 11791..11835, 11836..11880, 11881..11925, 11926..11970, 11971..12015, 12016..12060, 12061..12105, 12106..12150, 12151..12195, 12196..12240, 12241..12285, 12286..12330, 12331..12375, 12376..12420, 12421..12465, 12466..12510, 12511..12555, 12556..12600, 12601..12645, 12646..12690, 12691..12735, 12736..12780, 12781..12825, 12826..12870, 12871..12915, 12916..12960, 12961..13005, 13006..13050, 13051..13095, 13096..13140, 13141..13185, 13186..13230, 13231..13275, 13276..13320, 13321..13365, 13366..13410, 13411..13455, 13456..13500, 13501..13545, 13546..13590, 13591..13635, 13636..13680, 13681..13725, 13726..13770, 13771..13815, 13816..13860, 13861..13905, 13906..13950, 13951..13995, 13996..14040, 14041..14085, 14086..14130, 14131..14175, 14176..14220, 14221..14265, 14266..14310, 14311..14355, 14356..14400, 14401..14445, 14446..14490, 14491..14535, 14536..14580, 14581..14625, 14626..14670, 14671..14715, 14716..14760, 14761..14805, 14806..14850, 14851..14895, 14896..14940, 14941..14985, 14986..15030, 15031..15075, 15076..15120, 15121..15165, 15166..15210, 15211..15255, 15256..15300, 15301..15345, 15346..15390, 15391..15435, 15436..15480, 15481..15525, 15526..15570, 15571..15615, 15616..15660, 15661..15705, 15706..15750, 15751..15795, 15796..15840, 15841..15885, 15886..15930, 15931..15975, 15976..16020, 16021..16065, 16066..16110, 16111..16155, 16156..16200, 16201..16245, 16246..16290, 16291..16335, 16336..16380, 16381..16425, 16426..16470, 16471..16515, 16516..16560, 16561..16605, 16606..16650, 16651..16695, 16696..16740, 16741..16785, 16786..16830, 16831..16875, 16876..16920, 16921..16965, 16966..17010, 17011..17055, 17056..17100, 17101..17145, 17146..17190, 17191..17235, 17236..17280, 17281..17325, 17326..17370, 17371..17415, 17416..17460, 17461..17505, 17506..17550, 17551..17595, 17596..17640, 17641..17685, 17686..17730, 17731..17775, 17776..17820, 17821..17865, 17866..17910, 17911..17955, 17956..18000, 18001..18045, 18046..18090, 18091..18135, 18136..18180, 18181..18225, 18226..18270, 18271..18315, 18316..18360, 18361..18405, 18406..18450, 18451..18495, 18496..18540, 18541..18585, 18586..18630, 18631..18675, 18676..18720, 18721..18765, 18766..18810, 18811..18855, 18856..18900, 18901..18945, 18946..18990, 18991..19035, 19036..19080, 19081..19125, 19126..19170, 19171..19215, 19216..19260, 19261..19305, 19306..19350, 19351..19395, 19396..19440, 19441..19485, 19486..19530, 19531..19575, 19576..19620, 19621..19665, 19666..19710, 19711..19755, 19756..19800, 19801..19845, 19846..19890, 19891..19935, 19936..19980, 19981..20025, 20026..20070, 20071..20115, 20116..20160, 20161..20205, 20206..20250, 20251..20295, 20296..20340, 20341..20385, 20386..20430, 20431..20475, 20476..20520, 20521..20565, 20566..20610, 20611..20655, 20656..20700, 20701..20745, 20746..20790, 20791..20835, 20836..20880, 20881..20925, 20926..20970, 20971..21015, 21016..21060, 21061..21105, 21106..21150, 21151..21195, 21196..21240, 21241..21285, 21286..21330, 21331..21375, 21376..21420, 21421..21465, 21466..21510, 21511..21555