Exam 6: Using Probability to Make Decisions About Data

Suppose you are doing a poll of various attitudes for students at your college.You are especially interested in having an accurate representative sample based on student's geographical home area within the United States.Suppose at your college, 45% hail from the Northeast, 30% originate from the Midwest, 15% are from the West, and 10% are from the South.If you are looking to have a sample of 200 individuals, who should be included in order to have a representative sample?

At a carnival game, you'll win a prize if you pick a rubber duck out of a pool that has a red dot on the bottom.If only 3 ducks out of 95 present have such a dot, what is your probability of winning a prize?

In a test of physical fitness, a group of men ages 65 and older from a local retirement community were told to do as many sit-ups as they could.It is known the population mean $\mu$ is 20 with $\sigma_{X}=8$ The scores for the men from the retirement community are given below.Use a two-tailed rejection region with a total area of 0.05.What critical value should you use?

________tries to ensure that every member of a given population has an equal chance of inclusion in a given study.

If the population mean is 132, the sample mean is 136, $\left(\sigma_{X}^{2}\right)$ = 40, and N = 18, what is z?

What are the two fundamental reasons why a sample mean may differ from a particular population mean?

When +1.645 is used as the critical value instead of ±1.96 and the criterion probability is 0.05 in both cases,

What is the critical value?

Suppose you flip a fair coin five times.Which of the following combinations is most likely to occur? HHHHH HTHTH

When you see the symbol "p," it refers to

What can we conclude when the absolute value of a z-score for a sample mean is larger than the critical value?

Which of the following is not true of the criterion?

What is the probability of getting a sample mean between 500 and 520 if the population mean is 500 and the standard deviation of the sampling distribution the standard error of the mean) is 20?

When rolling a pair of fair dice, the probability of rolling a total point value of "7" is 0.17.If you rolled a pair of dice 1,000 times and the point value of "7" appeared 723 times, what would you probably conclude?

Suppose you flip a fair coin five times and get a "heads" each time.Your friend insists that your next flip certainly will come up as "tails." Is your friend correct?

The mean of the population $\sigma_{X}^{2}=100$ $(\mu)$ is 200 on a test measuring math skills of middle school students.The variance is .The test scores for the students in Mr.Petri's class at Suburban Middle School are given below.Use a rejection region with a probability of 5% only in the upper tail.What is the sample mean?

What is the purpose of the critical value?

A group of students were tested using a new software program.The researchers observed a sample mean of with a sample size of N = 20.They know the population mean is =42 \alpha=.05 $\mu=38$ and $\sigma=10$ , so they use and a one-tailed test to determine if their sample is greater than the known population mean.

If the standard error of the mean is 18 and the N is 36, what is $\sigma_{X}$ ?

In a test of physical fitness, a group of men ages 65 and older from a local retirement community were told to do as many sit-ups as they could.It is known the population mean $\mu$ is 20 with $\sigma_{X}=8$ The scores for the men from the retirement community are given below.Use a two-tailed rejection region with a total area of 0.05.What is the z- value?