Exam 6: Continuous Random Variables and the Normal Distribution

The tails of a normal distribution curve:

For the standard normal distribution,the area between z = -2.04 and z = 2.28,rounded to four decimal places,is:

Suppose that the random variable x has a binomial distribution with n = 30 and p = 0.48.You want to determine .Using the normal approximation,what is this probability? (Round the answer to 4 decimal places.)

For the standard normal distribution,the area to the right of z = -2.97,rounded to four decimal places,is:

For the standard normal distribution,the area between z = -2.35 and z = -1.56,rounded to four decimal places,is:

Use the following to answer questions : The net weights of all boxes of Top Taste cookies produce a distribution that is approximately normal with a mean of 31.74 and a standard deviation of 0.58. -The probability that the net weight of a randomly selected box of these cookies is more than 32.6 ounces,rounded to four decimal places,is:

The probability that a continuous random variable x assumes a single value is always:

Suppose that the distribution for a random variable x is normal with mean 15 and standard deviation ,and .Rounded to two decimal places,what is ?

The area under the standard normal curve from zero to z is 0.1772 and z is negative.The value of z is:

Use the following to answer questions : In a recent Gallup poll,52% of parents with children under 18 years of age gave themselves a grade of B for the job they are doing bringing up their kids.Assume that this percentage is true for the current population of all parents with children under 18 years of age.You take a random sample of 1044 such parents and ask them to give themselves a grade for the job they are doing bringing up their kids. -The probability that 560 or more will give themselves a grade of B is approximately: (Round the answer to 4 decimal places.)

A floor tiling contractor has just sent Tina out on a job without any indication of the size of the job.She does know that,over the years,the number of tiles required for each job has followed a normal distribution with a mean of 581 and a standard deviation of 210.She can either take the large truck (which is very difficult and expensive to drive)or the small truck to the job site.She is certain that the large truck can hold enough tiles to do the job,but she would prefer to take the small truck if she can.The small truck can carry up to 750 tiles.Because the job site is out of town,she can only make one trip.What is the probability that the small truck will carry enough tiles to do the job?

Use the following to answer questions : We know that 57% of all adults are in favor of abolishing the sales tax and increasing the income tax.Suppose we take a random sample of 420 adults and obtain their opinions on the issue. -The probability that 225 or fewer will be in favor of abolishing the sales tax and increasing the income tax is approximately:

For the standard normal distribution,the area between z = 0 and z = 1.70,rounded to four decimal places,is:

For a continuous random variable x,the probability that x assumes a value in an interval is:

Use the following to answer questions : We know that 57% of all adults are in favor of abolishing the sales tax and increasing the income tax.Suppose we take a random sample of 420 adults and obtain their opinions on the issue. -The probability that 250 to 265 will be in favor of abolishing the sales tax and increasing the income tax is approximately:

The total area under a normal distribution curve to the right of the mean is always:

Use the following to answer questions : The GMAT scores of all examinees who took that test this year produce a distribution that is approximately normal with a mean of 420 and a standard deviation of 32. -The probability that the score of a randomly selected examinee is between 400 and 480,rounded to four decimal places,is:

Let x have a normal distribution with a mean of -40.3 and a standard deviation of 11.51.The z value for x = -26.58,rounded to two decimal places,is:

We can use the normal distribution to approximate the binomial distribution when:

For a normal distribution,the z value for an x value that is to the right of the mean is always: