# Statistics: Multiple Choice Questions

1. An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is know to be $1,000. A random sample of 50 individuals resulted in an average income of $15,000. What sample size would the economist need to use if he wants a 95% confidence interval no wider than plus or minus $100?

1486 individuals

385 individuals

126 individuals

85 individuals

2. An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is know to be $1,000. A random sample of 50 individuals resulted in an average income of $15,000. What sample size would the economist need to use if he wants a 95% confidence interval no wider than plus or minus $100?

1486 individuals

385 individuals

126 individuals

85 individuals

3. In a non symmmetrical distribution:

the range equals the interquartile range

the interquartile range equals the mean

the median does not equal the mean

the variance equals the standard deviation

4.The Empirical Rule for the bell-shaped curve states that the percentage of data points falling within three standard deviations away from the mean is 99%

True

False

5.If we randomly draw a ball from a bag with a finite number of balls in it, then put the ball back into the bag and randomly draw another ball from the bag, this is an example of sampling with replacement

True

False

6. The area under the Normal probability curve is 1.

True

False

7. The Standard Normal distribution has a mean of 1 and a standard deviation of 1.

True

False

8. Distribution 1 is a skewed distribution and Distribution 2 is a symmetric distribution (not Normal distribution). Similar sample sizes will be required for the sample mean of random samples from the two distributions to have an approximate Normal distribution.

True

False

#### Solution Summary

This solution is comprised of detailed step-by-step calculation and explanation of the given problems. The solution also provides students with a clear perspective of the underlying statistical concepts.