STA 2

The mean score on a creativity test is 20 and a standard deviation is five the distribution is normal using the percentage approximations for the normal curve how many people would attain a score between 15 and 25 A. 34% B. 34%+34%=68% C. 50%

B. 34+34=68

The collection of all possible events is called A. A simple probability B. A sample space C. A joint probability D. The null set

B. A sample space

The fact that probabilities are proportions means that they A. Can be either a positive or a negative number B. Can it be lower than zero or more than 1 C. Have to be larger than one

B. Can it be lower than zero or more than 1

If one student is to be drawn from a group of students compromised of equal numbers of men and women to participate in a study of the effects of anxiety on test scores the probability of drawing a man or woman is said to be A. Multiplicative B. Dependent C. Conditional D. Additive

B. Dependent

If the outcome of an event A is not affected by event B, then events A and B are said to be A. Statistically independent B. Mutually exclusive C. Collectively exhaustive D. None of the above

B. Mutually exclusive

In statistics writing, it is common to use Greek letters for A. Quote sampling B. Population parameters C. Cross-sectional studies D. Haphazard sampling

B. Population parameters

The actual values of the mean variance and standard deviation of a population are called A. Population parameters B. Sample statistics C. Regressed standardized scores D. Population Z scores

B. Sample statistics

If the mean score on a stress scale is 5, the standard deviation is 2, and the distribution is normal the percentage of people who would obtain scores between 5 and 9 is A. 34+34=68 B. 14+34=48 C. 34 D. 50

B. 14+34=48

The z score for the student and his friend are

1.50,2.00

In a symmetrical distribution what percent of the scores fall above the mean A. 50% B.34% C. 95%

A. 50%

If 68% of IQ scores are between 85 and 115 what is the probability of meeting a person in the population within that IQ range A. 68 B. .068 C. 6.8

A. 68

Roughly ______ of the total area under the normal curve rests between two standard deviations above and below the mean A. 95% B. 99% C. 68% D. 47%

A. 95%

In its standardized form, the normal distribution A. Had a mean of 0 and standard deviation of 1 B. Has a mean of 1 and a variance if 0 C. Has an area equal to 0.5 D. Can not be approximated

A. Has a mean of 0 and standard deviation of 1

If two events are mutually exclusive what is the probability that one or the other occurs? A. 1.00 B. 0 C. .50 D. Can't be determined

B. 0

In figuring probabilities expected relative frequency is A. The result of an experiment B. The number of successful outcomes divided but the number of total outcomes expected if you repeat an experiment a large number of times C. How many time something happens

B. The number of successful outcomes divided by the number of total outcomes expected of you repeat an experiment a large number of times

If the mean of a test is 13 and a standard deviation is three the Z score for a person with the raw score of seven is A. -1 B. 1 C. -2 D. 2

C. -2

The probability of a student correctly guessing the answer to this question is A. .20 B. .30 C. .25 D. .50

C. .25

The raw score that corresponds to a Z score of 2.0 obtained from distribution with a mean of 80 and a standard deviation of 10 is A. 170 B. 82 C. 100 D. 90

C. 100

In how many ways can a girl choose a two-piece outfit from 5 blouses and 6 skirts? A. 60 B. 11 C. 30 D.13

C. 30

Using the percentage approximations for the normal curve, the percentage of scores between the mean and one standard deviation below the mean is A. 50% B. 50% C. 34% D. 14%

C. 34%

The normal curve is A. A theoretical idea B. Positively skewed C. Applicable to all real life research situations D. All of the above

C. Applicable to all real life research situations

Sampling distributions describe the distribution of A. Parameters B. Statistics C. Both parameters and statistics

C. Both parameters and statistics

If you want to know something about a population your results will be most accurate if you could study the A. Subgroup from the population B. Top 5% of people from the population C. Entire population

C. Entire population

The probability rule that applies when figuring the probability of getter both of two independent outcomes is the A. Addition rule B. Subtraction rule C. Multiplication rule D. Division rule

C. Multiplication rule

Choosing five people from a group of 23 people of which 15 or woman keeping track of the number of men chosen A. Not binomial: there are too many trials B. Procedure results in a binomial distribution C. Not binomial: the trials are not independent

C. Not binomial: the trial are not independent

Rolling a single die 30 times, keeping track of the fives rolled A. Not binomial: there are too many trials B. Not binomial: the trials are not independent C. Procedure results in a binomial distribution

C. Procedure results in a binomial distribution

Research that analyzes a portion of an entire population is carried out on a A. Census B. Survey C. Sample D. Population

C. Sample

The difference between the sample mean and the population mean is called A. Sample variance B. Mean variance C. Sampling error D. Population variance

C. Sampling error

If the expected value of a sample statistic is equal to the parameter it is estimating, then we call that sample statistic A. Random B. Biased C. Unbiased D. Minimum variance

C. Unbiased

The symbol for the mean of a population is A. o B. M C. u D. m

C. u

Empirical probabilities are A. Essentially percentages based on a large number of observations B. Deeply rooted in probability C. Scores from a sample D. Based on the normal curve

D. Based on the normal curve

Which of the following is not true of the normal curve A. It's total area contains 100% of the cases B. The mode, median, and mean are identical C. It is a probability distribution D. It is skewed

D. It is skewed

When determining the sample size necessary for estimating the true population mean, which factor is not considered when sampling with replacement A. The population standard deviation B. The allowable or tolerable sampling error C. The level of confidence desired in the estimate D. The population size

D. The population size

Probability is defined as

Number of times the outcome or event can occur divided by total number of times that any outcome or event can occur

The central limit theorem is important in statistics because A. for a large n, it says the sampling distribution of the sample mean is approximately normal regardless of the shape of the population B.

Shape of the population