Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 628019: Last fall, a sample of n = 36 freshmen was selected to participate in a new 4-hour training program designed to improve study skills. To evaluate the effectiveness of the new program, the sample was compared with the rest of the freshmen class. All freshmen must take the same English Language Skills course, and the mean score on the final exam for the entire freshmen class was u = 74.00. The students in the new program had a mean score of M = 86.40 with a standard deviation of s = 18.00. Test is the study skills training program produced a significant difference in scores usin an alpha = .01.
Click here to see answer by stanbon(57357)  |
Question 627984:
Assume you are the manager of a paint manufacturing factory. Your company has received complaints from customers that the containers hold less than the amount printed on them. On the other hand, corporate management is concerned that the containers hold more than the standard amount. You assign a statistician to verify these claims. A sample of containers was selected and the volume of paint in each container was measured. Assuming that the volume printed on each container is 1 gallon, how would you formulate the null and alternative hypotheses to test the customers’ claim? As a manager, what reasonable criteria will you use to set a value for the level of significance to be used in the test? After answering this question, what type of error would you suppose may result in that case?
Click here to see answer by stanbon(57357) |
Question 628060: Calculate the following for a z score of 0.74, with a
tail of 22.96%:
a. What percentage of scores falls below this z score?
b. What percentage of scores falls between the mean
and this z score?
c. What proportion of scores falls below a z score of
0.74?
Click here to see answer by stanbon(57357) |
Question 628068: A recent research report (Behenam & Pooya, 2006)
began, “There is probably no other area of health care
that requires a cooperation to the extent that orthodontics
does,” and explored factors that affected the
number of hours per day that patients wore their orthodontic
appliances. The patients in the study reported
that they used their appliances, on average,
14.78 hours per day, with a standard deviation of 5.31.
We’ll treat this group as the population for the purposes
of this example. Let’s say a researcher wanted
to study whether a DVD with information about orthodontics
led to an increase in the amount of time
patients wear their appliances but decided to use a
two-tailed test to be conservative. Let’s say he studied
the next 15 patients at his clinic, asked them to
watch the DVD, and then found that they wore their
appliances, on average, 17 hours per day.
a. What is the independent variable? What is the dependent
variable?
b. Did the researcher use random selection to choose
his sample? Explain your answer.
c. Conduct all six steps of hypothesis testing. Be sure
to label all six steps.
d. If the researcher’s decision in step 6 was wrong,
what type of error would he have made? Explain
your answer.
Click here to see answer by stanbon(57357) |
Question 436502: Blue Chips and Red Chips A bag contains 3 blue chips and 2 red chips. Chi and Dolly play the following game. Chi selects one chip at random from the bag. If Chi selects a blue chip, Dolly gives Chi $5. If Chi selects a red chip, Chi gives Dolly $8.
* a) Determine Chi’s expectation.
* b) Determine Dolly’s expectation.
You can put this solution on YOUR website!
Blue Chips and Red Chips A bag contains 3 blue chips and 2 red chips. Chi and Dolly play the following game. Chi selects one chip at random from the bag. If Chi selects a blue chip, Dolly gives Chi $5. If Chi selects a red chip, Chi gives Dolly $8.
--------------------
Random gain values for Chi: 5, -8
Corresponding Probabilities: 3/5, 2/5
------
* a) Determine Chi’s expectation.
E(x) = 5(3/5)-(8)(2/5) = 3-16/5 = -1/5 = -20 cents
--------------------------------------------------------
* b) Determine Dolly’s expectation.
Ans: +20 cents
Click here to see answer by risky38(1)  |
Question 628092: Billie wishes to test the hypothesis that overweight individuals tend to eat faster than normal-weight individuals. To test this hypothesis, she has two assistants sit in a McDonald’s restaurant and identify individuals who order the Big Mac special for lunch. The Big Mackers as they become known are then classified by the assistants as overweight, normal weight, or neither overweight nor normal weight. The assistants identify 10 overweight and 10 normal weight Big Mackers. The assistants record the amount of time it takes them to eight the Big Mac special.
1.0 585.0
1.0 540.0
1.0 660.0
1.0 571.0
1.0 584.0
1.0 653.0
1.0 574.0
1.0 569.0
1.0 619.0
1.0 535.0
2.0 697.0
2.0 782.0
2.0 587.0
2.0 675.0
2.0 635.0
2.0 672.0
2.0 606.0
2.0 789.0
2.0 806.0
2.0 600.0
a)Compute an independent-samples t-test on these data.
Report the t-value and the p values.
Where the results significant?
(Do the same thing you did for the t-test above, only this type when you go to compare means, click on independent samples t-test. When you enter group variable into grouping variable area, it will ask you to define the variables. Click define groups and place the number 1 into 1 and the number 2 into 2)??
b)What is the difference between the mean of the two groups?
What is the difference is standard deviation?
c)What is the null and alternative hypothesis?
Do the data results lead you to reject or fail to reject the null hypothesis?
d)What do the results tell you?
There seem to be a lot of typos. I copied the questions exactly as they are in the homework. I have been racking my brain and trying to figure these problems out using the text book but I am running out of time and need help understanding how to answer these questions. Thank you.
Click here to see answer by ewatrrr(10682)  |
Question 627896: A comittee of five persons is to be seleted andomly from a group of five men and 10 women. a) find the probability that the comittee consists of 2 men and 3 women b) find the probability that comittee consisting pf all the womens.
Click here to see answer by Susmitha(21)  |
Question 628112: Mr. Doodle’s grade distribution over the past 3 years for a course in college algebra is shown in the chart below.
Grade Number
A 45
B 180
C 210
D 95
F 65
I 5
If Jane plans to take a college algebra course with Mr. Doodle, determine the empirical probability that she receives at least a B.
Click here to see answer by ewatrrr(10682) |
Question 628128: spin the spinner in exercise 27-30, assume that the spinner cannot land on a line. Determine the probability that the spinner lands on (a)red, (b)green, (c)yellow,(d)blue. The picture of the circle is 1/2 green, 1/4 red, and 1/4 yellow.
Click here to see answer by ewatrrr(10682) |
Question 628151: 1)On average, 20 percent of the emergency room patients at Bedford hospital lack health insurance. In a random sample of 8 patients what is the probability that 2 will be uninsured?
2)On average, 20 percent of the emergency room patients at Bedford hospital lack health insurance. In a random sample of 8 patients what is the probability that 2 will be insured?
3On average, 20 percent of the emergency room patients at Bedford hospital lack health insurance. In a random sample of 8 patients what is the probability that no more than 1 patient is uninsured?
4) Consumers report on average 1.7 problems per vehicle with a popular make and model of a 2006 car. we randoly select a vehicle of the same make, model and year. what is the probability that it will have more than 3 problems
5. At an outpatient mental health clinic, appointment cancellations occur at a mean rate of 1.5 per day on a typical wednesday. What is the probability that less than 3 cancellations will occur on 2 wednesdays?
6 Thje pediatrics unit at Bedford hospital has 24 beds. The number of patients needing a bed at any point in time is normally distributed with a mean of 19.2 and standard deviation of 2.5. What is the probability that the number of patients needing a bed will exceed the pediatric unit bed capacity
Click here to see answer by ewatrrr(10682) |
Question 628166: The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Find the equation of the regression line for the given data. Predict the final exam score when a student studied for 4 hours. Predict the final exam score when a student studied for 6 hours.
Hours,x 3,5,2,8,2,4,4,5,6,3
scores,y 65,80,60,88,66,78,85,90,71
Click here to see answer by ewatrrr(10682) |
Question 628167: A manager wishes to determine the relationship between the number of miles (in hundreds of miles) the manager's sales representatives travel per month and the amount of sales (in thousands of dollars) per month. Find the equation of the regression line for the given data. Predict the value of sales when the sales representative travel 8 miles. Predict the value of sales when tthe sales representative traveled 11 miles.
Miles Traveled, x 2,3,10,7,8,15,3,1,11
Sales, y 31,33,78,62,65,61,48,55,120
Click here to see answer by ewatrrr(10682) |
Question 628169: Find the correlation coefficient between X and Y. Is there a weak or strong, positive or negative linear correlation between X and Y?
X -5,-3,4,1,-1,-2,0,2,3,-4
Y -10,8,9,1,-2,-6,-1,3,6,-8
Click here to see answer by ewatrrr(10682) |
Question 628196: A normally distributed population of scores has μ = 100 and σ = 5. Based on this information, solve the following questions:
a. If a sample consisting of n=36 scores is selected from this population, what is the probability that the sample will have M=98 or greater?
Click here to see answer by ewatrrr(10682) |
Question 628342: If the critical values for a statistical test are 1.96 and
1.96, determine if you would reject or fail to reject the
null hypothesis in each of the following cases:
a. z 1.06
b. z 2.06
c. A z score beyond which 7% of the data fall in each
tail
Click here to see answer by John10(245)  |
Question 628446: The Thomas Supply Company, Inc. is a distributor of gas-powered generators. As with any business, the length of time customers take to pay their invoices is important. Listed below, arranged from smallest to largest, is the time, in days, for a sample of The Thomas Supply Company, Inc. invoices.
13
13
13
20
26
30
32
33
34
34
35
35
36
37
38
41
41
41
45
46
47
47
49
52
54
55
56
62
67
82
(Round your answers to 2 decimal places.)
(a) Determine the first and third quartiles.
Q1 =
Q3 =
(b) Determine the second decile and the eighth decile.
D2 =
D8 =
(c) Determine the 67th percentile.
Click here to see answer by stanbon(57357) |
Question 628493: Essay; show all work. the property restoration company PuroServ is considering switching to new dehumidifiers. Their market research, considering the cost of the new machines and their efficiency, tells them that the switch would give them a 75% chance of making a $20,000 profit, a 20% chance of breaking even, and a 5% chance of losing $5,000. How much money does PuroServ expect to make with their new purchase?
Click here to see answer by stanbon(57357) |
Question 628513: The ages in the data set can be shown to be approximately normally distributed with a mean of 50 years and a standard deviation of 6 years. A person is randomly selected and their age observed. Find the probability that their age will fall between 55 and 60.
Now I got some of it: Z = (55-50/6) = (5/6) = 0.8333 = 0.2967 My question is where does 0.2967 come from?
How is that calculated from Z = (55-50/6) = (5/6) = 0.8333?
Please tell me how to enter it in my calculator. Thank you in advance.
Click here to see answer by John10(245) |
Question 628526: 3. A group consists of 4 men and 3 women.
a) In how many ways can 3 people be selected from the group of 7?
b) In how many ways can 3 people be selected if they are all men?
c) What is the probability that the selected group will be all men?
Click here to see answer by nerdybill(6959)  |
Question 628483: The attendance for a week at a local theatre is normally distributed, with a mean of 4000 and a standard deviation of 500. Draw the normal curve to represent the normally distributed attendance for the week. What percentage of the attendance would be less than 3500? What percentage of the attendance would be greater than 5000? What percentage of the attendance figures would be between 3700 and 4300 each week?
Am I supposed to try and solve this from the graph or can it be calculated?
Thank you for your help.
Click here to see answer by ewatrrr(10682) |
Question 628489: A person spins the pointer and is awarded the amount indicated by the pointer.
In a pie chart there is half of the pie at $2, the other half is split in two one being $10 and the other being $15,
It costs $8 to play the game. Determine:
The expectation of a person who plays the game.
The fair price to play the game
Show work for full credit
Click here to see answer by ewatrrr(10682) |
Question 628601: Essay; show all work. A simple dartboard has three areas, the main board has a radius of 8 inches, there is a circle with a radius of 6 inches, and the bullseye has a radius of 4 inches. What is the probability of a random dart landing inside the bullseye? Round to the nearest thousandth
Click here to see answer by richwmiller(9143)  |
Question 628652: Problem 6)
A government survey conducted to estimate the mean price of houses in a metropolitan area is designed to have a margin of error of $10,000. Pilot studies suggest that the population standard deviation is $70,000. Estimate the minimum sample size needed to estimate the population mean with the stated accuracy.
Problem 7)
A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 490 college students showed that 33% of them had, or intended to, cheat on examinations. Find the margin of error for the 95% confidence interval.
Click here to see answer by John10(245) |
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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, 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