Stats final 2/2 Questions and Answers 2024
A sample of 25 elements is selected to estimate a 98% confidence interval for the variance of the
population. The chi-square values to be used for this interval estimation are:
12.401 and 39.364.
15.695 and 33.196.
10.856 and 42.980.
13.848 and 36.415. ** Answ** 10.856 and 42.980.
The value of F.01 with 10 numerator and 20 denominator degrees of freedom is:
2.94.
3.37.
2.39.
2.91. ** Answ** 3.37.
A sample of 20 elements is selected to estimate a 90% confidence interval for the variance of the
population. The chi-square values to be used for this interval estimation are:
8.907 and 32.852.
11.651 and 27.204.
7.633 and 36.191.
10.117 and 30.144. ** Answ** 10.117 and 30.144.
What percent of the sampling distribution lies above F.05 with 9 degrees of freedom in the
numerator and 14 degrees of freedom in the denominator?
5%
12%
2.5%
10% ** Answ** 5%
We can use the chi-square distribution to develop interval estimates and conduct hypothesis tests
about a population variance as long as the data comes from a:
,1. stratified random sample, selected from a unimodal population.
2. random sample, selected from a right skewed population.
3. random sample, selected from a normal population.
4. systematic random sample, selected from a right skewed population. ** Answ** 3.
random sample, selected from a normal population.
Which of the following is the point estimator of the population variance?
s
s2
σ
σ2 ** Answ** s2 (2 = squared)
An F distribution has:
1. n1 - 1 degrees of freedom in the numerator and n2 - 1 degrees of freedom in the denominator.
2. a uniform distribution.
3. a left skewed distribution.
4. values that range from to -∞ to ∞. ** Answ** 1. n1 - 1 degrees of freedom in the
numerator and n2 - 1 degrees of freedom in the denominator.
An egg packing company has stated that the standard deviation of the weights of their grade A
large eggs is 0.07 ounces or less. The sample variance for 53 eggs was 0.0062 ounces. Can the
sample result confirm the company's claim? The test statistic is . Find the p-value.
1. The p-value is between 0.01 and 0.05.
2. The p-value is greater than 0.10.
3. The p-value is less than 0.01.
4. The p-value is between 0.05 and 0.10. ** Answ** 4. The p-value is between 0.05 and
0.10.
A one-tailed hypothesis test about two population variances will always be formulated as:
an upper tail test.
a multi-sided test.
, a lower tail test.
a two-sided test. ** Answ** an upper tail test.
When the level of significance is 0.10, and the sample size is 19, the chi-square value for a one-
tailed test (lower tail) is
10.09.
12.44.
11.65.
10.86. ** Answ** 10.86.
What values among the provided ones the random variable for a chi-square distribution may
assume?
-2.173, 0, 5.991
2.535, 3.121, 5.772
0, 4.229, 7.888
-9.885, -6.378, -5.331 ** Answ** 2.535, 3.121, 5.772
A sample of 21 observations yielded a sample variance of 16. If we want to test H0 : σ2 = 16, the
test statistic is:
21.
50.
20.
5. ** Answ** 20
The standard deviation of the ages of a sample of 16 executives from City A on the east coast
was 5.2 years, while the standard deviation of the ages of a sample of 21 executives from City B
on the west coast was 12.8 years. We would like to know if there is any difference in the
population variances of the ages of all the east coast and west coast executives. Determine the
test statistic.
F = 2.44
F = 6.06
A sample of 25 elements is selected to estimate a 98% confidence interval for the variance of the
population. The chi-square values to be used for this interval estimation are:
12.401 and 39.364.
15.695 and 33.196.
10.856 and 42.980.
13.848 and 36.415. ** Answ** 10.856 and 42.980.
The value of F.01 with 10 numerator and 20 denominator degrees of freedom is:
2.94.
3.37.
2.39.
2.91. ** Answ** 3.37.
A sample of 20 elements is selected to estimate a 90% confidence interval for the variance of the
population. The chi-square values to be used for this interval estimation are:
8.907 and 32.852.
11.651 and 27.204.
7.633 and 36.191.
10.117 and 30.144. ** Answ** 10.117 and 30.144.
What percent of the sampling distribution lies above F.05 with 9 degrees of freedom in the
numerator and 14 degrees of freedom in the denominator?
5%
12%
2.5%
10% ** Answ** 5%
We can use the chi-square distribution to develop interval estimates and conduct hypothesis tests
about a population variance as long as the data comes from a:
,1. stratified random sample, selected from a unimodal population.
2. random sample, selected from a right skewed population.
3. random sample, selected from a normal population.
4. systematic random sample, selected from a right skewed population. ** Answ** 3.
random sample, selected from a normal population.
Which of the following is the point estimator of the population variance?
s
s2
σ
σ2 ** Answ** s2 (2 = squared)
An F distribution has:
1. n1 - 1 degrees of freedom in the numerator and n2 - 1 degrees of freedom in the denominator.
2. a uniform distribution.
3. a left skewed distribution.
4. values that range from to -∞ to ∞. ** Answ** 1. n1 - 1 degrees of freedom in the
numerator and n2 - 1 degrees of freedom in the denominator.
An egg packing company has stated that the standard deviation of the weights of their grade A
large eggs is 0.07 ounces or less. The sample variance for 53 eggs was 0.0062 ounces. Can the
sample result confirm the company's claim? The test statistic is . Find the p-value.
1. The p-value is between 0.01 and 0.05.
2. The p-value is greater than 0.10.
3. The p-value is less than 0.01.
4. The p-value is between 0.05 and 0.10. ** Answ** 4. The p-value is between 0.05 and
0.10.
A one-tailed hypothesis test about two population variances will always be formulated as:
an upper tail test.
a multi-sided test.
, a lower tail test.
a two-sided test. ** Answ** an upper tail test.
When the level of significance is 0.10, and the sample size is 19, the chi-square value for a one-
tailed test (lower tail) is
10.09.
12.44.
11.65.
10.86. ** Answ** 10.86.
What values among the provided ones the random variable for a chi-square distribution may
assume?
-2.173, 0, 5.991
2.535, 3.121, 5.772
0, 4.229, 7.888
-9.885, -6.378, -5.331 ** Answ** 2.535, 3.121, 5.772
A sample of 21 observations yielded a sample variance of 16. If we want to test H0 : σ2 = 16, the
test statistic is:
21.
50.
20.
5. ** Answ** 20
The standard deviation of the ages of a sample of 16 executives from City A on the east coast
was 5.2 years, while the standard deviation of the ages of a sample of 21 executives from City B
on the west coast was 12.8 years. We would like to know if there is any difference in the
population variances of the ages of all the east coast and west coast executives. Determine the
test statistic.
F = 2.44
F = 6.06
