7 Questions About Statistics
The scores of one student on two different IQ tests are as follows:
IQ Test A IQ Test B
X=140 X=120
Mean=105 Mean=100
S=20 S=10
ZA = ZB =
Which test did the student do better on test A or test B?
Using the Z table and the answer from test A on question 1 above what percentage of students did the student do better than? (Find the area under the curve to solve.)
If a z score is 1.23, what is the area under the curve?
Use the following table to calculate the correlation coefficient (r).
and Interpret the results in words.
| Cost ($10K) | Development Time (Months) |
| 59 | 54 |
| 54 | 68 |
| 59 | 69 |
| 58 | 71 |
| 71 | 78 |
| 55 | 59 |
| 55 | 69 |
| 54 | 67 |
A pharmaceutical company wants to know which drug treatment is best for people who suffer from anxiety. Participants are assigned to three different treatment groups (A, B &C) and asked to complete the Liebowitz Social Anxiety Scale. Below are the results for each treatment group after the treatment was administered.
| Group A | Group B | Group C |
| 62 | 42 | 80 |
| 81 | 52 | 57 |
| 75 | 31 | 87 |
| 58 | 80 | 64 |
| 67 | 22 | 28 |
| 48 | 71 | 29 |
| 26 | 68 | 62 |
| 36 | 76 | 45 |
| 25 | 23 | 18 |
| 42 | 31 |
a. State the null and research hypothesis
b. Set the level of risk
c. Select the appropriate test
d. Compute the obtained value.
e. Find the critical value
f. Compare the obtained value and the critical value.
g. State your decision.
h. Write the result
The average annual expenditure for health care by men is $1,096 with a standard deviation of $205 and women is $1,234 with a standard deviation of $310. A random sample of 10 men and 10 women were selected. Test to see if the mean expenditure for men is different then the mean expenditure for women.
a. State the null and research hypothesis
b. Set the level of risk
c. Select the appropriate test
d. Compute the obtained value.
e. Find the critical value
f. Compare the obtained value and the critical value.
g. State your decision.
h. Write the result
Five groups of listeners are tested on a speech intelligibility task with signals with signals presented at the same sensation level to all listeners. The groups are (a) normal hearing listeners (n=10), (b) listeners with a mild conductive hearing loss (n=10), (c) listeners with a moderate conductive hearing loss (n=10), (d) listeners with a mild sensorineural hearing loss (n=10), and (e) listeners with a moderate sensorineural hearing loss (n=10). Between group variance = 700, within-group variance = 309. Identify the degree’s of freedom. Identify the critical value.
