Math 210 Test 3 Name__________________________
Multiple choice problems (1 – 13) are 3 pts each. Circle the letter of the best answer.
1. What is the value of t*, the critical value of the t distribution with 8 degrees of
freedom, that satisfies the condition that the probability is .10 of being larger than t*?
a) 1.397 b) 1.282 c) 2.896 d) .90
2. Do students tend to improve their SAT Mathematics (SAT_M) score the second time they take the
test? A random sample of four students who took the test twice received the following scores.
Student # 1 2 3 4
First Score 450 520 720 600
Second Score 440 600 720 630
To analyze this data we should
a) use the one-sample t-test b) use the matched pairs t test
b) use the two-sample t test d) consider any of the above valid, it is at the
experimenter’s discretion.
3. Researchers compared two groups of competitive rowers—a group of skilled rowers and a
group of novices. The researchers measured the angular velocity of each subject’s right knee,
which describes the rate at which the knee joint opens as the legs push the body back on the
sliding seat. The sample sizes, the sample means, and the sample standard deviations for the
two groups are given below.
Group n Mean Standard deviation
Skilled 16 4.2 .6
Novice 16 3.7 .8
The data showed no strong outliers or skewness, so the researchers decided to use the two-
sample t procedures. A 90% confidence interval for skilled - novice is (use the conservative value
for the degrees of freedom):
a) .5 0.011 b) .5 .25 c) .5 .44 d) .5 1.753
4. For the rower data in the problem above, the researchers wished to test the hypotheses
Ho: the mean knee velocities for skilled and novice rowers are the same
Ha: the mean knee velocity for skilled rowers is larger than for novice rowers
The data showed no strong outliers or strong skewness so the researchers decided to use the
two-sample t test. The value of the two-sample t test statistic is:
a) .25 b) .5 c ) 2.0 d) 4.0
