STATS: CHAPTER 8

A sample of size 25 is drawn from a population where 56% of the population is over the age of 40. In the sample, 45% are over the age of 40. What is the value of p in this example? A: 0.45 B : 0.55 C : 0.56 D : 0.25

C

Which of the following distributions expresses the relationship between the sample variance and population variance?

chi-squared

A sample of size 25 is drawn from a population where 39% of the population is over the age of 40. In the sample, 41% are over the age of 40. Which is the z score for this result?

.20

A sample of 24 is drawn from a population with a variance of 4.6. The sample variance is 4.2. The chi-square statistic for this example is

21

A sample of size 20 is drawn from a population where 44% of the population is over the age of 40. In the sample, 48% are over the age of 40. Which is the correct formula for the denominator of the z score to compute a confidence interval for the population proportion? A: 0.48×0.5220‾‾‾‾‾‾‾‾√0.48×0.5220 B: 0.44×0.5620−1‾‾‾‾‾‾‾‾√0.44×0.5620-1 C: 0.48×0.5220−1‾‾‾‾‾‾‾‾√0.48×0.5220-1 D: 0.44×0.5620‾‾‾‾‾‾‾‾√0.44×0.5620

A

The t distribution formula for estimating the population mean is used when which piece of information is unknown? A :μ B: σ C: s D: n

B

A sample of size 49 is drawn from a population with a mean of 40. The sample mean is 45. For purposes of calculating sample size, error of estimation or E in this example is calculated as A : (45-40)/7. B : 45-40. C : (45 - 40)/48. D : (45-40)/49.

b

A sample of size 28 is drawn from a population and the t statistic calculated. The t distribution for this problem has what degrees of freedom?

27

For a two-sided 90% confidence interval, what percentage of the total probability will be in each tail?

5

A confidence interval is calculated as 100±(1.96)1540√100±(1.96)1540 What is the confidence level associated with this confidence interval?

95

In computing a confidence interval, the largest value for z would be found in what size of confidence interval?

99

All else held equal, which of the following confidence intervals will require the largest sample size to produce a satisfactory estimate?

99%

All else being held equal, which of the following will result in a smaller t statistic? A: smaller n B: smaller μ C: smaller σ D: smaller s

a

What sample size is necessary to calculate a 95% confidence interval if the estimate should be within 2 units of the true value and σ = 4? A : 16 B : 30 C : 31 D : 15

a

A sample has a range from 3 to 37. The standard deviation of the population from which it was drawn is unknown. An estimate of the population standard deviation can be calculated as A : (37 - 3)/3. B : (37 - 3)/4. C : (37 - 3 - 1)/4. D : (37 - 3 - 1)/3.

b

All else held equal, which of the following will result in a larger value for the chi-square statistic relating the sample variance to the population variance? A: smaller s B: larger μ C: larger n D: larger σ

c

All else being equal, which of the following will result in a larger value for the z score when estimating the population proportion? A: larger σ B: larger p C: larger pˆp^ D: larger n

d

Which of the following sample sizes would be expected to yield a t distribution closest to the standard normal distribution? A n = 20 B n = 15 C n = 30 D n = 50

d

Which of the following is an example of a point estimate?

sample mean