1. If the test value for the difference between the means of two large samples is 2.57 when the critical value is

1.96, what decision should be made?

A) Reject the null hypothesis.

B) Accept the null hypothesis.

C) Reject the alternative hypothesis.

D) Accept the equality hypothesis.

2. An educational researcher is analyzing the test scores for physics students

taught using two different methods a traditional method, and a webbased self

paced method. Can he conclude, at α = .05, that the test scores in the web

based selfpaced method are lower?

Traditional Webbased Selfpaced

Sample size 50 40

Mean test score 80 76

Population variance 26 42

A) The data does not support the claim because the test value 1.27 is less

than the critical value 1.65.

B) The data does not support the claim because the test value 1.27 is less

than the critical value 1.96.

C) The data supports the claim because the test value 3.19 is greater than

the critical value 1.96.

D) The data supports the claim because the test value 3.19 is greater than

the critical value 1.65.

3. A group of college students believes the average grades in psychology

courses are different than the average grades in biology courses. The group

found the average psychology grades of a sample of 11 students was 84.4 and

the average biology grades of a sample of 11 students was 78.2. What is the null

hypothesis for this study?

A) H0: µ = 84.4 and 78.2

B) H0: µpsychology = 84.4 and H0: µbiology = 78.2

C) H0: µpsychology + µbiology = 162.6

D) H0: µpsychology = µbiology

4. A reporter bought hamburgers at randomly selected stores of two

different restaurant chains, and had the number of Calories in each hamburger

measured. Can the reporter conclude, at α = 0.05, that the hamburgers from the

two chains have a different number of Calories?

Chain A Chain B

Sample size 5 9

Sample mean 230 Cal 285 Cal

Sample standard deviation 23 Cal 29 Cal

A) No, because the test value –0.28 is inside the noncritical region 2.306 < t <

2.306

B) Yes, because the test value –0.28 is inside the noncritical region 2.776 < t <

2.766

C) Yes, because the test value –3.90 is outside the noncritical region 2.776 < t

< 2.776

D) No, because the test value –1.26 is inside the noncritical region 2.306 < t <

2.306

5. A running coach wanted to see whether runners ran faster after eating

spaghetti the night before. A group of six runners was randomly chosen for this

study. Each ran a 5 kilometer race after having a normal dinner the night before,

and then a week later, reran the same race after having a spaghetti dinner the

night before. The times for their races are shown in the table below. What test

value should be used in a t test for these dependent samples?

Runner 1 Runner 2 Runner 3 Runner 4 Runner 5

Runner 6

Regular Dinner 1,000 s 985 s 1,009 s 970 s 1,016 s 996

s

Spaghetti Dinner 992 s 979 s 1,005 s 968 s 1,016 s 998

s

A) 3.80

B) 0.80

C) 1.55

D) 1.96

6. A poll found that 41% of male voters and 44% of female voters support a

particular candidate. To test whether this candidate has equal levels of support

between male and female voters, the null hypothesis should be:

A) H0: pmale = pfemale

B) H0: pmale = 50%, H0: pfemale = 50%

C) H0: pmale = 41%, H0: pfemale = 44%

D) H0: pmale < pfemale