What is the technique used by scientists to standardize the normal curve?
The standard normal curve has an area of . . .
The standard normal curve always has a mean of . . .
If a z-score is negative, then the area associated with that score will also be negative.
An empirical distribution consisting of raw scores taken from a population is referred to as what by research scientists?
Approximately 68% of a sample falls within one and negative one standard deviation from the mean.
The central limit theorem states . . .
Which of the following is an important distinction between the z and t distributions?
Which of the following is true of probabilities?
The probability of rolling a 4 on one toss of a standard six-sided die is:
The probability of rolling a 4 or a 6 on one toss of a standard six-sided die is:
The probability of rolling a 4 on one toss of a standard six-sided die and a 6 on a second toss is:
Which of the following is true of the normal distribution?
Which of the following is NOT true of the normal curve?
Roughly ______% of the total area under the normal curve rests between two standard deviations above and below the mean.
The difference between the sample mean and the population mean is called:
Question #1 (10 points)
Criminologists have long thought that living in a “broken home” (i.e., non-two-parent home) is a strong risk factor for delinquency. The following cross-tabulation shows the joint distribution of family structure with self-report delinquent status. Use this table to answer the question below.
Family Structure | ||||
Delinquent? | Two Parents | Single Mother | No Mother Figure | Total |
No | 2894 | 1160 | 346 | 4400 |
Yes | 2673 | 1352 | 469 | 4494 |
Total | 5567 | 2512 | 815 | 8894 |
Compute the probability of delinquency conditional on living with two parents, a single mother, and no mother figure. Note that you will compute three probabilities.
Question #2
Compute a standard score for a score of 25 in which the mean is 22 and the standard deviation is 2.5.
Question #3.
The following data show a contingency table of the association between political affiliation and support for the death penalty. Answer the following questions using this table.
Support Death Penalty? | |||
Party | Support | Oppose | Total |
Republican | 13 | 6 | 19 |
Democrat | 14 | 7 | 21 |
Independent | 2 | 8 | 10 |
Total | 29 | 21 | 50 |
Question #4.
In 2000, there were 6,498,562 adults under correctional supervision. During this same year, the U.S. adult (i.e., 18 or older) population was estimated to be 202,682,000.
Compute the probability that a randomly selected adult in the U.S. is under correctional supervision.
Question #5.
Suppose that state-level unemployment rates are normally distributed with mean 4.14 and standard deviation 1.04. Use these as your population values, and calculate the following probabilities.
Question #6.
The percent of area beyond z = 1.44 is ___________.
Question 7
The percent of TOTAL cases that have a z score less than or equal to 1.46 is_____.
Question 8
The probability of obtaining a score between z = -1.40 and the mean is _________.
Question #9.
The percent of area between the mean and z = 1.45 is ___________.