Statistics Questions

1. In a large population of adults, the mean IQ is 112 with a standard deviation of 20. Suppose 200 adults are randomly selected for a market research campaign. The distribution of the sample mean IQ is

(a) Exactly normal with mean 112 and standard deviation 20.

(b) Approximately normal with mean 112 and standard deviation of 0.1.

(c) Approximately normal with mean 112 and standard deviation of 1.414.

(d) Approximately normal with mean 112 and standard deviation of 20.

2. The weights of extra large eggs have a normal distribution with a mean of 1 oz. and a standard deviation of 0.1 oz. The probability that a dozen eggs weighs more than 13 oz. is closest to

(a) | 0.0000 | (b) | 0.0020 | (c) | 0.1814 | (d) | 0.2033 |

The student body of a large university consists of 60% female students. A random sample of 8 students is selected.

3. What is the probability that among the students in the sample exactly two are female?

(a) | 0.0896 | (b) | 0.2936 | (c) | 0.0413 | (d) | 0.0007 |

4. What is the probability that among the students in the sample at least 7 are female?

(a) | 0.1064 | (b) | 0.0896 | (c) | 0.0168 | (d) | 0.8936 |

5. The mean and the variance of the female students in the sample are

(a) | 4.8 and 1.92 | (b) | 3.2 and 1.92 | (c) | 4.8 and 1.39 | (d) | 3.2 and 1.39 |

6. The central limit theorem states if the sample size n is large then

(a) The distribution of the observations (the sample data) is approximately normal.

(b) The distribution of the sample mean is approximately standard normal.

(c) The distribution of the sample mean is approximately normal.

(d) The distribution of the population mean is approximately normal.

7. An airplane is only allowed a gross passenger weight of 8000 kg. If the weights of passengers traveling by air between Toronto and Vancouver have a mean of 78 kg and a standard deviation...