Statistics and Probability Answers

b. A stamping device for University of Lusaka reception is not working properly and producing 15% defectives. The defective and no defective stampings proceed from the machine on a random manner.
i. If 4 stampings are randomly collected, find the probability that 2 of them are defective. [4 Marks]
ii. Find the mean, variance and standard deviation?

What is the probability that Mike spends at most 240 min on online gaming if his mean time spent on it is 270 min with a standard deviation time of 15 min?

The population mean weight of a candy is 10 grams with a standard deviation of 2 grams. A sample of 100 candies is taken. What is the probability that the sample mean differs from the population mean by at most 0.3 gram?

The population mean weight of a candy is 10 grams with a standard deviation of 2 grams. A sample of 100 candies is taken. What is the probability that the sample mean is at least 10.6 grams?

The population mean weight of a candy is 10 grams with a standard deviation of 2 grams. A sample of 100 candies is taken. What is the probability that the sample mean is 9.7 grams or lower?

The population mean weight of a candy is 10 grams with a standard deviation of 2 grams. A sample of 100 candies is taken. What is the probability that the sample mean is between 9.4 and 10.4 grams?

The population mean weight of a candy is 10 grams with a standard deviation of 2 grams. A sample of 100 candies is taken. What is the probability that the sample mean is 10.5 grams or lower?

Smart TVs have seen success in the United States market. During the 2nd quarter of
2015 45% of TVs sold in the United States were Smart TVs. That’s an increase of 11% from 2014.
Choose three households and find the probability that
(a) None of the 3 households had a Smart TV
(b) All 3 households had a Smart TV
(c) At least 1 of the 3 households had a Smart TV

The weights of 10 boxes of a certain brand of cereal have a mean content of 278 grams with a standard deviation of 9.64 grams. If these boxes were purchased at 10 different stores and the average price per box is $1.29 with a standard deviation of $0.09, can you conclude that the weights are relatively more homogeneous than the prices?

Suppose that 55% of all babies born in a particular hospital are boys. If 7 babies born in the hospital are randomly selected, what is the probability that fewer than 3 of them are boys? Carry your intermediate computations to at least four decimal places, and round your answer to two decimal places.