# Statistics - Multiple Choice Questions

1) If Larry gets a 70 on a physics test where the mean is 65 and the standard deviation is 5.8, where does he stand in relation to his classmates? (Points: 5)

He is in the top 10%.

He is in the top 20%.

He is in the bottom 20%.

He is in the bottom 10%.

2. Let's assume you have taken 100 samples of size 64 each from a normally distributed population. Calculate the standard deviation of the sample means if the population's variance is 49. (Points: 5)

0.875

0.125

0.766

0.587

3. Find P(11 < x < 16) when mu = 15 and sigma = 3. (Points: 5)

0.6293

0.3707

0.0918

0.5375

4. Interpret a 90% confidence interval of (4.355, 4.445) for a population mean.

5. ) In the standard normal distribution, the variance is always (Points: 5)

0

1

2

none of these

6. The area under a normal curve with mu = 15 and sigma = 2 is (Points: 5)

0

1

2

none of these

https://brainmass.com/statistics/variance/275110

#### Solution Preview

(1) z = (x - m)/s = (70 - 65)/5.8 = 0.8621

P(z > 0.8621) = 0.1943 or (19.43%), which means Larry is in the top 20%, ...

#### Solution Summary

Complete and Correct answers are provided.