# Random probability of ping-pong ball selection

1) The diameter of Ping- Pong balls manufactured at a large factory is expected to be approximately normally distributed with a mean of 1.30 inches and a standard deviation of 0.40 inch. What is the probability that a randomly selected Ping-Pong ball will have a diameter between 1.31 and 1.33 inches?

A) 0.0987 (B) 0.1747 (C) 0.2734 (D) 0.3721

2) The width of confidence interval estimate for a proportion will be:

A) narrower for 99% confidence than for 95% confidence (B) wider for a sample size of 100 than for a sample size of 50. (C) narrower for 90% confidence than for 95% confidence (D) narrower when the sample proportion is 0.50 than when the sample proportion is 0.20

11) The use of the finite population correction factor when sampling without replacement from finite populations will:

A) increase the standard error of the mean (B) not affect the standard error of the mean (C) reduce the standard error of the mean. (D) only affect the proportion, not the mean.

9) For air travelers, one of the biggest complaints is of the waiting time between when the airplane taxis away from the terminal until the flight take off. This waiting time is known to have a skewed-right distribution with a mean of 10 minutes and a standard deviation of 8 minutes. Suppose 100 flights have been randomly sampled. Describe the sampling distribution of the mean waiting time between when the airplane taxis away from the terminal until the flight takes off for these 100 flights.

A) Distribution is skewed-right with mean= 10 minutes and the standard error=0.8 minutes (B) Distribution is skewed-right with mean= 10 minutes and the standard error= 8 minutes (C) Distribution is approximately normal with mean = 10 minutes and standard error =0.8 minutes (D) Distribution is approximately normal with mean = 10 minutes and standard error = 8 minutes

[Please see the attached question file for all the 11 questions.]

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#### Solution Summary

Answers with a brief calculation/explanation wherever required have been provided..