1) A room in a laboratory is only considered safe if the mean radiation level is 400 or less. When a sample of 10 radiation measurements were taken, the mean value of the radiation was 414 with a standard deviation of 17. There are concerns that mean radiation is above 414. Radiation levels in the lab are known to follow a normal distribution with standard deviation 22. We will like to conduct a hypothesis test at the 5% level of signicance to determine whether there is evidence that the laboratory is unsafe.

What will be the appropriate test?

a)z-test

b)t-test

c)ANOVA

d)Chi-square

2)

If I wanted to test for association using chi-square test, whether there is an association between gender (Male or Female) and tenure-ship (tenured or not tenured), what will be my degree of freedom?

3)

The P-value for a normally distributed right-tailed test is P=0.042. Which of the following is INCORRECT?

a--We will reject H0 at =0.05, but not at =0.01

b--The P-value for a two-tailed test based on the same sample would be P=0.084

c--The P-value for a left-tailed test based on the same sample would be P= -0.042

d--The z-score test statistic is approximately z=1.73

4)

The time X taken by a cashier in a grocery store express lane to complete a transaction follows a normal distribution with mean 90 seconds and standard deviation 20 seconds.What is the first quartile of the distribution of X (in seconds)?

a)81.2

b)88.0

c)73.8

d)76.6

5)

A man accused of committing a crime is taking a polygraph (lie detector) test. The polygraph is essentially testing the hypotheses

H0: The man is telling the truth vs. Ha: The man is not telling the truth.

Suppose we use a 5% level of significance. Based on the man's responses to the questions asked, the polygraph determines a P-value of 0.08. We conclude that:

a)We reject the null hypothesis as there is sufficient evidence that the man is telling the truth.

b)We fail to reject the null hypothesis as there is insufficient evidence that the man is not telling the truth.

c)The probability that the man is telling the truth is 0.08.

d)The probability that the man is not telling the truth is 0.08.