Statistics Test 1c Prof. VanderHoff Spring 2003
All work must be shown on exam to receive credit.
Use the following data [from a sample] for problems 1-3:
X Y
|
|
|
|
|
|
11 |
3 |
|
|
|
|
|
|
|
|
4 |
9 |
|
|
|
|
|
|
|
|
6 |
1 |
|
|
|
|
|
|
|
|
8 |
4 |
|
|
|
|
|
|
|
|
3 |
7 |
|
|
|
|
|
|
|
|
10 |
6 |
|
|
1. [25] Calculate the following statistics for variable X:
Mean:
Median
Mode
Range
Variance
Standard
deviation
Coefficient
of variation
2. [20] Calculate the following statistics for X and Y:
Covariance
Correlation coefficient
3. [5] Calculate the Z score for the following values of Y:
|
0 |
|
|
5 |
|
|
10 |
|
4. [10] Calculate the GPA using the data on grades and credits:
|
gragrade |
crecredits |
|
4 |
35 |
|
3.5 |
3 |
|
3 |
25 |
|
2.5 |
15 |
|
2 |
12 |
|
1.5 |
15 |
|
1 |
9 |
|
0 |
6 |
5. [5] From a group of 12 students, how many different groups of 2 could be chosen to sit in the front row.
6. [10]. The probability that a parking place is available in deck I is .8 and the probability that a parking place is available in deck II is .6. [assume independence] Calculate the probabilities
|
|
|
|
|
PaParking available in both decks |
|
|
|
PaParking available in only one deck |
|
|
|
PaParking not available in either deck |
|
|
7. [10] The probability it snows is .7 and the probability class is canceled is .4. What is the probability it snows and class is canceled?
. What is the probability it snows or class is canceled?
8. [7] The probability class end early is .5 and the probability a test is returned in class is .2. The probability that class ends early and a test is returned is .1. Show whether the events that class end early and a test is returned are independent.
9. [8] The mean time to commute is 40 minutes and the standard deviation is 10 minutes.
About 68% of the commutes are between ----------- and --------------.
About 95% of the commutes are between ----------- and --------------.