3.40 Explain why there must be a mistake in each of the following statements: (a) The probability that a student will get an \( A \) in a geology course is 0.3 , and the probability that he or she will get either an \( A \) or a \( B \) is 0.27 . (b) A company is working on the construction of two shopping centers; the probability that the larger one will be completed on time is 0.35 and the probability that both will be completed on time is 0.42 .

A researcher believes that \( 8 \% \) of pet dogs in Europe are Labradors. If the researcher is right. what is the probability that the proportion of Labradors in a sample of 630 pet dogs would be greater than \( 7 \% \) ? Round your answer to four decimal places.

sample of size 110 will be drawn from a population with mean 36 and standard deviation 14 . Use the \( O \) cumulative Normal Distribution Table if needed. Part: \( 0 / 2 \) Part 1 of 2 (a) Find the probability that \( \bar{x} \) will be between 33 and 38 . Round the final answer to at least four decimal places. The probability that \( \bar{x} \) will be between 33 and 38 is

The mean per capita consumption of milk per year is 126 liters with a standard deviation of 24 liters. If a sample of 100 people is randomly selected, what is the probability that the sample mean would be less than 122.27 liters? Round your answer to four decimal places.

Suppose that the walking step lengths of adult males are normally distributed with a mean of 2.3 feet and a standard deviation of 0.4 feet. A sample of 83 men's step lengths is taken. Step 2 of 2 : Find the probability that the mean of the sample taken is less than 2.1 feet. Round your answer to 4 decimal places. if necessary.

Each year, a group surveys 50,000 households to study internet usage. In one area of the study, the group is interested in finding out how many hours a day the household spends streaming video from the internet. Describe the five basic steps in a statistical study with an example of their application below. Describe the second step in this statistical study. Choose the correct answer below. A. Choose a representative sample from the population. In this case, it would be choosing a sample of 50,000 households. B. Start collecting data. In this case, we randomly call phone numbers and ask them about their internet habits. C. Redefine the goal of your study. In this case, we also want to discover how many hours per day a household spends checking email. D. Choose a representative sample from the population. In this case, it would be choosing a small sample from the 50,000 households.