MyMathLab Homework Answers

Qn 21.
Use the Standard Normal Table or technology to find the z-score that corresponds to the cumulative area 0.9023
Qn22.

Find the z-score that has 48.4% of the distribution’s area to its left.
Qn23.
The weights of bags of baby carrots are normally distributed, with a mean of 34 ounces and a standard deviation of 0.37 ounce. Bags in the upper 4.5% are too heavy and must be repackaged. What is the most a bag of baby carrots can weight and not need to be repackaged?
A bag of baby carrots can weight at most ounces without needing to be repackaged.

Hint: Find the z-score that corresponds to a certain area by locating
that area in the Standard Normal Table. The values at the beginning of
the corresponding row and at the top of the corresponding column give
the z-score. In most cases, the area will not be an entry in the
table. In these cases, use the entry closest to it. When the area is
halfway between two area entries, use the z-score halfway between the
corresponding z-scores. Technology can also be used to find the
z-score. To transform a standard z-sc0re to an x-value in a given
population, use the formula x = u = zsigma, where u is the population
mean and sigma is the population standard deviation.

Qn24.
A population has a mean mu = 84 and a standard deviation sigma = 16. Find the mean and standard deviation of a sampling distribution of a sample means with sample size n = 64.