Statistics 1060: Practice Solutions Week 7

- 4.61
We know the standard deviation of a distribution is the square root of the variance, .

From the practice problems from Week 6, , so

(3 - 2.25)

^{2}(0.30) + (4 - 2.25)^{2}(0.15) = 1.3875. So .

- 4.65
Since the two times are independent, the total variance is . So seconds.

- 4.69
- a)
Now a simple calculation,
C and
.
So
C.
- b)
Mean = 0
^{o}C, standard deviation = 5.701^{o}C. - c)
F and
F.

- 5.3
- a)
Yes. It is reasonable to assume that the results for the 50 students are independent, and each has the same chance of passing.
- b)
No. Since the student recieves instruction after incorrect answers, her probability of success is likely to increase.
- c)
No. Temperature may affect the outcome of the test.

STATISTICS 1060 HOMEPAGE | PREVIOUS PAGE |