Question

1.Suppose a normally distributed set of data with 6200 observations has a mean of 116 and a standard deviation of 19. Use the 68-95-99.7 Rule to determine the number of observations in the data set expected to be above a value of 135. Round your answer to the nearest whole value.

2.A manufacturer knows that their items have a normally distributed lifespan, with a mean of 9.5 years, and standard deviation of 1.6 years.

The 9% of items with the shortest lifespan will last less than how many years?

Give your answer rounded to one decimal place.

Warning: Do not use the Z Normal Tables...they may not be accurate enough since WAMAP may look for more accuracy than comes from the table.

3.A particular fruit's weights are normally distributed, with a mean of 457 grams and a standard deviation of 25 grams.

The heaviest 13% of fruits weigh more than how many grams?

(Give your answer to the nearest gram.)

Warning: Do not use the Z Normal Tables...they may not be accurate enough since WAMAP may look for more accuracy than comes from the table.

Answer 1

1) We need to find

Using 68-95-99.7 rule and the symmetry of normal distribution about mean, the required probability is

2) The life times has distribution . We need to find the 9th percentile,

3) The weights has distribution . We need to find the 100-13=87th percentile,

What is WAMAP ?