Question

A)

The amounts of nicotine in a certain brand of cigarette are normally distributed with a mean of 0.941 g and a standard deviation of 0.319 g. The company that produces these cigarettes claims that it has now reduced the amount of nicotine. The supporting evidence consists of a sample of 30 cigarettes with a mean nicotine amount of 0.848 g.

Assuming that the given mean and standard deviation have NOT changed, find the probability of randomly selecting 30 cigarettes with a mean of 0.848 g or less.
P(x-bar < 0.848 g) =
Enter your answer as a number accurate to 4 decimal places.

B)

A particular fruit's weights are normally distributed, with a mean of 243 grams and a standard deviation of 10 grams.

If you pick 21 fruit at random, what is the probability that their mean weight will be between 248 grams and 249 grams

C)

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 6.3 years, and standard deviation of 1 years.

If 5 items are picked at random, 2% of the time their mean life will be less than how many years?

Give your answer to one decimal place.

Answer 1

A)

B)

C)