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Tutors Answer Your Questions about Describing-distributions-with-numbers (FREE)
Question 1174328: In a survey of a company, mean salary of employees is MYR29,321 with standard deviation of MYR2,120. Consider the sample of 100 employees and find the probability their mean salary will be less than MYR29,000? (Hint: use central limit theorem).
Click here to see answer by CPhill(1987)   |
Question 1174329: From past claims data for a particular insurance business, an insurance company considers that claims for the coming year will have a mean size of RM5000 and standard deviation of RM7500. Claim sizes are assumed to have a lognormal distribution. Estimate the probability of claims exceeding RM20000.
Click here to see answer by CPhill(1987) |
Question 1178024: The final grade in statistics of 80 student at AAMUSTED Mathematics level100 are recorded below,
68 84 75 82 68 90 62 88 76 93
73 79 88 73 60 93 71 59 85 75
61 65 75 87 74 62 95 78 63 72
66 78 82 75 94 77 69 74 68 60
96 78 89 61 75 95 60 79 83 71
79 62 67 97 78 85 76 65 71 75
65 80 73 57 88 78 62 76 53 74
86 67 73 81 72 63 76 75 85 77
1:Using the sturge's approximation rule construct a frequency distribution table for the data above
2:Use the table to calculate;
* Mean and standard deviation
* Skewness and kurtosis.
Click here to see answer by CPhill(1987) |
Question 1186302: A manufacturing company regularly conducts quality control
checks at specified periods on the products it manufactures.
Historically, the failure rate for LED light bulbs that the company
manufactures is 5%. Suppose a random sample of 10 LED light
bulbs is selected. What is the probability that
a. none of the LED light bulbs are defective?
b. exactly one of the LED light bulbs is defective?
c. two or fewer of the LED light bulbs are defective?
d. three or more of the LED light bulbs are defective?
Click here to see answer by CPhill(1987) |
Question 1190376: A graduate psychology student finds that 64% of all first semester calculus students in Prof. Mean’s
class have a working knowledge of the derivative by the end of the semester.
a) Take X = percentage of students who have a working knowledge of calculus after 1 semester,
and find a beta density function that models X, assuming that the performance of students in
Prof. Mean’s is average.
b) Find the median of X (rounded to two decimal places) and comment on any difference between
the median and the mean.
Density function of the β- distribution is given by
f(x) = (β + 1)(β + 2)x^β(1 − x); x ∈ [0; 1], β > 0
Click here to see answer by CPhill(1987) |
Question 1191145: Find some means. Suppose that X is a random variable with mean 20 and standard deviation 2. Also suppose that Y is a random variable with mean 40 and standard deviation 7. Assume that the correlation between X and Y is zero. Find the mean of the random variable Z for each of the following cases. Be sure to show your work.
A)Z=25−12X.
B)Z=13X−8.
C)Z=X+Y.
D)Z=X−Y.
E)Z=−3X+3Y
Click here to see answer by CPhill(1987) |
Question 1204046: The amount of caffeine in a sample of 250ml servings of brewed coffee is summarized in the table below:
Caffeine (mg) Number of cups
60 < 80 : 1
80 < 100 : 12
100 < 120 : 25
120 < 140 : 10
140 < 160 : 2
2.1 Calculate the average caffeine content of the 250ml cup
2.2 Calculate the modal caffeine content of the 250ml cup.
2.3 Calculate the median caffeine content of the 250ml cup.
2.4 Calculate the standard deviation of the content of the 250ml cup
Click here to see answer by ElectricPavlov(122) |
Question 1209043: Dave's GRE average score is 600 with standard deviation of 120 points. What is the standard score for a person who scores 730? Rita's GRE average score is 450 with standard deviation of 130 points. What is the standard score for a person who scores 720? Who did better on the GRE in terms of the mean?
Click here to see answer by ikleyn(52864)  |
Question 1205250: The weights for newborn babies is approximately normally distributed with a mean of 6.5 pounds and a standard deviation of 1.8 pounds
Consider a group of 1300 newborn babies
1. How many would you expect to weigh between 3 and 7 pounds?
2. How many would you expect to weigh less than 6 pounds?
3. How many would you expect to weigh more than 4 pounds?
4. How many would you expect to weigh between 6.5 and 10 pounds?
Click here to see answer by MathLover1(20850)  |
Question 1204047: Potato chip lovers do not like soggy chips, so it is important to find characteristics of the production process that produces chips with an appealing texture.
The following sample data on the frying time (in seconds) and moisture content (%) of potato chips were collected:
Frying time (X) Moisture content (Y)
65 1.4
50 1.9
35 3
30 3.4
20 4.2
15 8.1
10 9.7
5 16.3
3.1 Draw a scatter diagram to represent the two variables.
3.2 Calculate the Pearson’s correlation coefficient.
3.3 Comment on the strength of the relationship between the two variables.
3.4 Determine the linear regression equation.
3.5 Estimate the moisture content of chips that were fried for 25 seconds.
Click here to see answer by Theo(13342)  |
Question 1203964: The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.9 days and standard deviation of 1.3 days. Use your graphing calculator to answer the following questions. Write your answers in percent form. Round your answers to the nearest tenth of a percent.
a) What is the probability of spending less than 8 days in recovery?
b) What is the probability of spending more than 4 days in recovery?
c) What is the probability of spending between 4 days and 8 days in recovery?
Click here to see answer by ikleyn(52864) |
Question 1201185: In the claims department of an insurance office various quantities are
computed at the end of each day’s business. On Monday, 20 claims are
received for a particular class of policy. The mean claim amount is calculated
to be K4,500 and the standard deviation to be K2,540. On Tuesday, the
claims are reviewed and one claim which was incorrectly recorded as K13,000
is now corrected to K3,000. Determine the mean and standard deviation of
the corrected set of claims
Click here to see answer by Theo(13342) |
Question 1198939: Which of the following two sets of numbers is true of the center and spread?
a) 2,3,6,8,9
b) 4,5,7,8,9
One of the following is the correct answer. Which one?
A) the median is the same but set b has the larger IQR
B) the b set has the larger median and IQR
C) set b has the larger median and smaller IQR
D) the IQRs are the same but set b has the larger median.
Click here to see answer by MathLover1(20850) |
Question 1198517: Scores for a common standardized college aptitude test are normally distributed with a mean of 518 and a standard deviation of 113. Randomly selected students are given a Test Preparation Course before taking this test. Assume, for sake of argument, that the preparation course has no effect.
If 1 student is randomly selected, find the probability that their score is at least 553.4.
P(X > 553.4) =
Enter your answer as a number accurate to 4 decimal places.
If 20 students are randomly selected, find the probability that their mean score is at least 553.4.
P(
¯¯¯
X
X
¯
> 553.4) =
Click here to see answer by ewatrrr(24785)  |
Question 1197769: Suppose that grade point averages of undergraduate students at one university have a bell-shaped distribution with a mean of 2.62 and a standard deviation of 0.4 Using the empirical rule, what percentage of the students have grade point averages that are at least 1.82? Please do not round your answer.
Click here to see answer by math_tutor2020(3817) |
Question 1197532:
x
P
(
x
)
x
2
x
P
(
x
)
x
2
P
(
x
)
0 0.22
0
Correct
0
Correct
0
Correct
1 0.15
1
Correct
0.15
Correct
0.15
Correct
2 0.18
4
Correct
0.36
Correct
0.72
Correct
3 0.16
9
Correct
0.48
Correct
1.44
Correct
4 0.29
16
Correct
1.16
Correct
4.64
Correct
Find the mean. Round to two decimal places.
μ
=
Find the standard deviation. Round to three decimal places.
σ
=
Click here to see answer by ikleyn(52864) |
Question 1197517: Questions 24-25
The scores of a standardized IQ test are normally distributed with a mean score of 100 and a standard deviation of 15.
Question 24
Find the probability that a randomly selected person has an IQ score higher than 105.
Question options:
0.9522
0.3694
-1.15
0.6306
Question 25
A random sample of 55 people is selected from this population. What is the probability that the mean IQ score of the sample is greater than 105?
Question options:
0.0067
0.3694
0.6306
0.9933
Click here to see answer by ewatrrr(24785) |
Question 1195153: The heights of the adult male population on a given island are normally distributed with mean 70 inches and standard deviation of 2.5 inches.
(a.) what percentage of heights is within 1 standard deviation of the mean? That is, what percentage of heights is between 70-2.5=67.5 inches and 70+2.5=72.5 inches?
(b.) what percentage of male population are shorter than 65 inches?
(c.) what percentage of males are taller than 67 inches?
(d.) what percentage is between 67 and 68 inches?
Click here to see answer by ikleyn(52864) |
Question 1194722: Analyze the given data below and answer the following questions:
Zian's Scores in Math and English
ENGLISH: 50, 40, 28, 35, 37
MATH: 36, 29, 35, 30, 35
MEASURES OF VARIABILITY ENGLISH
Mean 38
Standard Deviation 8.03
Variance 64.5
RAnge 22
MEASURES OF VARIABILITY MATH
Mean 33
Standard Deviation 3.24
Variance 10.5
RAnge 7
Question 1:In what subject does Zian performs well?
Question 2: In what subject does Zian shows consistent score?
Question 3: Are his scores in english are more spread out than math?
Click here to see answer by Alan3354(69443)  |
Question 1191285: The time taken for a student to complete an exam is normally distributed with a mean of 40 minutes and a standard deviation of 5.5 minutes.
The probability a student takes between k and 48 minutes is 0.4. What is the value of k?
Click here to see answer by Boreal(15235)  |
Question 1191287: The time taken for a student to complete an exam is normally distributed with a mean of 40 minutes and a standard deviation of 5.5 minutes.
A student is randomly selected. What is the probability that the student completes the task in less than 48 minutes?
Click here to see answer by ikleyn(52864) |
Question 1191028: I am having trouble on a problem from my homework assignment. This is the question word for word from the text book:
The average earnings of year-round full-time workers 25-34 years old with a bachelor's degree or higher were $58,500 in 2003. If the standard deviation is $11,200, what can you say about the percentage of these workers who earn;
a. between $47,300 and $69,700?
b. More than $80,900?
c. How likely is it that someone earns more than $100,000?
Click here to see answer by ikleyn(52864) |
Question 1191028: I am having trouble on a problem from my homework assignment. This is the question word for word from the text book:
The average earnings of year-round full-time workers 25-34 years old with a bachelor's degree or higher were $58,500 in 2003. If the standard deviation is $11,200, what can you say about the percentage of these workers who earn;
a. between $47,300 and $69,700?
b. More than $80,900?
c. How likely is it that someone earns more than $100,000?
Click here to see answer by MathLover1(20850) |
Question 1188632: The number of potholes in any given 1 mile stretch of freeway pavement in Pennsylvania has a bell-shaped distribution. This distribution has a mean of 46 and a standard deviation of 11. Using the empirical rule, what is the approximate percentage of 1-mile long roadways with potholes numbering between 35 and 79?
Click here to see answer by Shin123(626)  |
Question 1188632: The number of potholes in any given 1 mile stretch of freeway pavement in Pennsylvania has a bell-shaped distribution. This distribution has a mean of 46 and a standard deviation of 11. Using the empirical rule, what is the approximate percentage of 1-mile long roadways with potholes numbering between 35 and 79?
Click here to see answer by Solver92311(821)  |
Question 1186716: ] Assuming that the 26 letters in the English language alphabet comprise a
population,
1. Briefly explain how a simple random sample of size n = 7 can be obtained
with no mode(s). No calculations would be involved.
2. Showing your work, find the total number of simple random samples of
size n = 7 possible, none having any mode.
3. Showing your work, what is the probability of drawing a simple random
sample of size n = 7 containing the set A, B, C, D, X, Y, Z, using a 6-ball
capacity scoop and at first attempt, from a bag containing 26 ping pong balls,
each uniquely labeled one of the 26 letters?
Click here to see answer by Edwin McCravy(20062)  |
Question 1182257: A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1462 and the standard deviation was 319. The test scores of four students selected at random are 1890,1180 ,2210,and 1350. Find the z-scores that correspond to each value and determine whether any of the values are unusual.
The z-score for 1890 is____?
Round to two decimal places as needed.)
Click here to see answer by math_tutor2020(3817) |
Question 1179100: 100 students attended a party, 79 were interviewed and 54 of the 79 met the case definition of the disease.
53 took the drink and out of them 50 is sick and 3 is well.
26 did not take the drink and out them 4 is sick and 22 is well.
1. What is the association between the drink and illness
2. The attributable proportion for the drink
Click here to see answer by ikleyn(52864) |
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