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?...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 <
B) Yes, because the test value –0.28 is inside the noncritical region 2.776 < t <
C) Yes, because the test value –3.90 is outside the noncritical region 2.776 < t
D) No, because the test value –1.26 is inside the noncritical region 2.306 < t <
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
Regular Dinner 1,000 s 985 s 1,009 s 970 s 1,016 s 996
Spaghetti Dinner 992 s 979 s 1,005 s 968 s 1,016 s 998
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