A random sample of size 15 taken from a normally distributed population revealed a sample mean of 75 ...

A random sample of size 15 taken from a normally distributed population revealed a sample mean of 75 and a sample variance of 25 . The upper limit of a 95 confidence interval for the population mean would equal:
 a. 77.77 c. 88.85
  b. 72.23 d. 77.27

Q. 2

The Kruskal-Wallis test can be used to test for a difference between two populations. It will produce the same outcome as the two-tail Wilcoxon rank sum test.
  Indicate whether the statement is true or false

Q. 3

A robust estimator is one that is:
 a. unbiased and symmetrical about zero. c. efficient and less spread out.
  b. consistent and is also mound-shaped. d. not sensitive to moderate nonnormality.

Q. 4

Suppose using Kruskal-Wallis test, there are five samples, and the value of the test statistic is calculated as H = 12.32 . Then the most accurate statement that can be made about the p-value of the test is that it is greater than 0.025 but smaller than 0.05
  Indicate whether the statement is true or false

Q. 5

Researchers determined that 60 Puffs tissues is the average number of tissues used during a cold. Suppose a random sample of 100 Puffs users yielded the following data on the number of tissues used during a cold: = 52 and s = 22 . Suppose the test statistic does not fall in the rejection region at  = 0.05 . Which of the following conclusions is correct?
 a. At  = 0.05, we do not reject H0 . c. At  = 0.05, we accept H0.
  b. At  = 0.05, we reject H0 . d. Both a and c.

Q. 6

The critical value is taken from the F-distribution whenever the test is a Kruskal-Wallis test.
  Indicate whether the statement is true or false

Q. 7

For statistical inference about the mean of a single population when the population standard deviation is unknown, the degrees for freedom for the t-distribution equal n - 1 because we lose one degree of freedom by using the:
 a. sample mean as an estimate of the population mean.
  b. sample standard deviation as an estimate of the population standard deviation.
  c. sample proportion as an estimate of the population proportion.
  d. sample size as an estimate of the population size.