## A study of an association between which ear is used for cell phone calls

A study of an association between which ear is used for cell phone calls and whether the subject is​ left-handed or​ right-handed began with a survey​ e-mailed to 5000 people belonging to an otology online​ group, and 717 surveys were returned.​ (Otology relates to the ear and​ hearing.) What percentage of the 5000 surveys were​ returned? Does that response rate appear to be​ low? In​ general, what is a problem with a very low response​ rate?

## MyMathLab Binomial Probability Questions

Qn22.
Write the binomial probability in words. Then, use a continuity correction to convert the binomial probability to a normal distribution probability.
P(x = 81)

## Write the probability in words

.
Which of the following is the normal probability statement that corresponds to the binomial probability statement?
a. P(x < 81.5)
b. P(X > 81.5)
c. P(80.5 < x < 81.5)
d. P(x>80.5)
e. P(x < 80.5)
Qn23.
A student answers all 48 questions on a multiple-choice test by guessing. Each question has four possible answers, only one of which correct. Find the probability that the student gets exactly 15 correct answers. Use the normal distribution to approximate the binomial distribution.

`````` *Answer., 0.0823, 0.8577, 0.0606, 0.7967*

``````

## 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.

## Determine whether the random variable X is discrete or continuous

Qn11. Determine whether the random variable X is discrete or continuous. Explain.
Let x represent the amount of rain in City B during April.

Qn12. Find the mean variance, and standard deviation of the binomial distribution with the given values of n and p.
Qn13. Complete parts (a) and (b) below.
The number of dogs per household in a small town

Find the mean, variance, and standard deviation of the probability distribution.

## Example probability Question - MyMathLab homework

Qn8. A group of students were asked if they carry a credit car.. The responses are listed in the table.

If a student is selected at random, find the probability that he or she is a sophomore given that the student owns a credit card. Round you answers to three decimal places.
Qn9. A card is selected at random from a standard deck of 52 playing cards. Find the probability of each event.
a. Randomly selecting a black suit or a jack.
b. Randomly selecting a heart or an 8
c. Randomly selecting 1 10 or face card.
Q10. The accompanying table shows the numbers of male and female students in a particular country who received bachelor’s degrees in business in a recent year. Complete parts (a) and (b) below.

Find the probability that a randomly selected student is male, given that the student received a business degree.