Question 1

What are the properties of a normal distribution?

Accepted Answer

Normal distributions are symmetric. The mean, median, and mode all have the same value. Approximately 68% of the cases are within 1 standard deviation of the mean; approximately 95% of the cases are within 2 standard deviation of the mean; Approximately 99.7% of the cases are within 3 standard deviation of the mean.

Question 2

A researcher takes a sample of 500 employed college graduates and asks them how long it took them to find a job after college. In the sample the average length of time was 65 days. Our researcher estimates the value of the standard error to be 5 days. Complete the following statements:
A) The sample result was __________ with a margin of error of ___________ and a level of confidence of 68 percent.
B) I am 95 percent sure that the true average # of days to find a job after college is between __________ and __________.

Accepted Answer

a. 65 days … 5 days
b. 55 days … 75 days

Question 3

Which of the following statements is correct?

Accepted Answer

A)  As the sample size increases, the standard error decreases. 
B)  Standard errors of sampling distributions can be calculated from the results of non-probability samples. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct. 
A)  As the sample size increases, the standard error decreases. 
B)  Standard errors of sampling distributions can be calculated from the results of non-probability samples. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct. A

Question 4

A researcher measured the pulse of a random sample of runners finishing the Boston Marathon. The results of the study were sample size = 100, sample mean = 160, and sample standard deviation = 20. What is the best estimate for the standard error of the sampling distribution? __________

Accepted Answer

The answer of A researcher measured the pulse of a...

Question 5

A variable is normally distributed. Approximately what percent of cases have values within two standard deviations of the mean?

Accepted Answer

A)  50% 
B)  68% 
C)  95% 
D)  99.7% 
A)  50% 
B)  68% 
C)  95% 
D)  99.7%

Question 6

A researcher takes a sample of 500 professional sociologists. In the sample the average annual income for the sociologists is $100,000. Our researcher estimates the value of the standard error to be $500. Complete the following statements:
A) The sample result was __________ with a margin of error of ___________ and a level of confidence of 95 percent.
B) I am 95 percent sure that the true average annual income for sociologists is between __________ and __________.

Accepted Answer

a. $100,00

Question 7

A variable is normally distributed with a mean of 50, a standard deviation of 5, and a variance of 25. What is the value of its median?

Accepted Answer

A)  5 
B)  25 
C)  50 
D)  100 
A)  5 
B)  25 
C)  50 
D)  100

Question 8

That sampling distributions based on large samples are normal distributions is proven by

Accepted Answer

A)  the Central Limit Theorem 
B)  Gauss' Axiom 
C)  the Thomas Theorem 
D)  Zipf's Law 
A)  the Central Limit Theorem 
B)  Gauss' Axiom 
C)  the Thomas Theorem 
D)  Zipf's Law

Question 9

What three things affect the size of the standard error?

Accepted Answer

the size of the sample, the ty

Question 10

Which of the following statements is correct?

Accepted Answer

A)  As the variation in the population decreases, the standard error decreases. 
B)  Researchers prefer to have a small standard error. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct. 
A)  As the variation in the population decreases, the standard error decreases. 
B)  Researchers prefer to have a small standard error. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct.

Question 11

The center of a sampling distribution corresponds on the number to the

Accepted Answer

A)  parameter value 
B)  sample size 
C)  sampling error 
D)  standard error 
A)  parameter value 
B)  sample size 
C)  sampling error 
D)  standard error

Question 12

The length of time presidents of universities stay in office is normally distributed with a mean of 5 years and a standard deviation of 2 years. What percent of university presidents stay in office
A) More than 9 years? __________
B) Less than 3 years? __________
C) Between 3 and 7 years? __________
D) Is this problem about a frequency distribution or a sampling distribution? (frequency / sampling)
E) What is the median number of years university presidents stay in office? __________

Accepted Answer

a. 2.5%
b.

Question 13

Which of the following statements is correct?

Accepted Answer

A)  Researchers prefer to have a small standard error. 
B)  As the standard error increases, the width of the 95% confidence interval decreases. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct. 
A)  Researchers prefer to have a small standard error. 
B)  As the standard error increases, the width of the 95% confidence interval decreases. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct.

Question 14

A researcher takes a sample of 500 NFL football fans. In the sample the average size of their largest home TV is 54 inches. Our researcher estimates the value of the standard error to be 3 inches. Complete the following statements: "I am 68 percent sure that the true average size for NFL football fans of their largest home TV is between __________ and __________."

Accepted Answer

A)  3 inches … 54 inches 
B)  53 inches … 55 inches 
C)  52 inches … 56 inches 
D)  51 inches … 57 inches 
A)  3 inches … 54 inches 
B)  53 inches … 55 inches 
C)  52 inches … 56 inches 
D)  51 inches … 57 inches

Question 15

_____ are characteristics of populations; _____ are characteristics of samples.

Accepted Answer

A)  parameters … statistics 
B)  pointers … values 
C)  statistics … parameters 
D)  values … pointers 
A)  parameters … statistics 
B)  pointers … values 
C)  statistics … parameters 
D)  values … pointers

Question 16

Which sampling distribution will typically have the smallest standard error?

Accepted Answer

A)  a sampling distribution based on samples from a population with a variance of 5 
B)  a sampling distribution based on samples from a population with a variance of 25 
C)  a sampling distribution based on samples from a population with a variance of 90 
D)  a sampling distribution based on samples from a population with a variance of 100 
A)  a sampling distribution based on samples from a population with a variance of 5 
B)  a sampling distribution based on samples from a population with a variance of 25 
C)  a sampling distribution based on samples from a population with a variance of 90 
D)  a sampling distribution based on samples from a population with a variance of 100

Question 17

What does the central limit theorem say about sampling distributions?

Accepted Answer

Sampling distributions based o

Question 18

If scores on the SAT exam are normally distributed with a mean of 1000 and a standard deviation of 200, what percent of persons score
A) Above 1400? __________
B) Between 600 and 1200? __________
C) Below 800? __________
D) Is this problem about a frequency distribution or a sampling distribution? (frequency / sampling)

Accepted Answer

a. 2.5%
b.

Question 19

What is the difference between a standard deviation and a standard error?

Accepted Answer

Standard deviation is a measure of dispe

Question 20

Which of the following statements is correct?

Accepted Answer

A)  A probability sample will always give you a result within one standard error of the true value (census value) in the population. 
B)  Most variables are normally distributed in the population but very few sampling distributions are normal distributions. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct. 
A)  A probability sample will always give you a result within one standard error of the true value (census value) in the population. 
B)  Most variables are normally distributed in the population but very few sampling distributions are normal distributions. 
C)  Both "a" and "b" are correct. 
D)  None of the above is correct.

What are the properties of a normal distribution?

Which of the following statements is correct?

A researcher measured the pulse of a random sample of runners finishing the Boston Marathon. The results of the study were sample size = 100, sample mean = 160, and sample standard deviation = 20. What is the best estimate for the standard error of the sampling distribution? __________

A variable is normally distributed. Approximately what percent of cases have values within two standard deviations of the mean?

A variable is normally distributed with a mean of 50, a standard deviation of 5, and a variance of 25. What is the value of its median?

That sampling distributions based on large samples are normal distributions is proven by

What three things affect the size of the standard error?

Which of the following statements is correct?

The center of a sampling distribution corresponds on the number to the

Which of the following statements is correct?

_ are characteristics of populations; _ are characteristics of samples.

Which sampling distribution will typically have the smallest standard error?

What does the central limit theorem say about sampling distributions?

If scores on the SAT exam are normally distributed with a mean of 1000 and a standard deviation of 200, what percent of persons score A) Above 1400? B) Between 600 and 1200? C) Below 800? __ D) Is this problem about a frequency distribution or a sampling distribution? (frequency / sampling)

What is the difference between a standard deviation and a standard error?

Which of the following statements is correct?

Introduction

Data Sets

Frequency Tables and Univariate Charts

Central Tendency and Dispersion

Creating New Variables

Comparing Group Means

Crosstab Tables

Nominal and Ordinal Measures of Association

Pearsons Correlation and Bivariate Regression

Multiple Regression

Hypothesis Testing and One-Sample T Tests

Paired and Independent-Samples T Tests

Analysis of Variance

Chi-Square

Hypothesis Testing With Measures of Association and Regression

Filters

Exam 11: Sampling Distributions and Normal Distributions

What are the properties of a normal distribution?

Which of the following statements is correct?

A researcher measured the pulse of a random sample of runners finishing the Boston Marathon. The results of the study were sample size = 100, sample mean = 160, and sample standard deviation = 20. What is the best estimate for the standard error of the sampling distribution? __________

A variable is normally distributed. Approximately what percent of cases have values within two standard deviations of the mean?

A variable is normally distributed with a mean of 50, a standard deviation of 5, and a variance of 25. What is the value of its median?

That sampling distributions based on large samples are normal distributions is proven by

What three things affect the size of the standard error?

Which of the following statements is correct?

The center of a sampling distribution corresponds on the number to the

Which of the following statements is correct?

_____ are characteristics of populations; _____ are characteristics of samples.

Which sampling distribution will typically have the smallest standard error?

What does the central limit theorem say about sampling distributions?

What is the difference between a standard deviation and a standard error?

Which of the following statements is correct?

Introduction

Data Sets

Frequency Tables and Univariate Charts

Central Tendency and Dispersion

Creating New Variables

Comparing Group Means

Crosstab Tables

Nominal and Ordinal Measures of Association

Pearsons Correlation and Bivariate Regression

Multiple Regression

Hypothesis Testing and One-Sample T Tests

Paired and Independent-Samples T Tests

Analysis of Variance

Chi-Square

Hypothesis Testing With Measures of Association and Regression

Filters

_ are characteristics of populations; _ are characteristics of samples.