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25 Cards in this Set
 Front
 Back
Which of the following is true of probabilities? 
A probability varies from 0 to 1.0 

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

In a symmetrical distribution, what percent of the scores fall above the mean? 
50% 

About 75% of the scores in a normal distribution fall between the mean and three standard deviations above the mean. 
False 

Roughly __________ of the total area under the normal curve rests between the mean and one standard deviation above. 
34% 

Roughly __________ of the total area under the normal curve rests between two standard deviations above and below the mean. 
95% 

Probability is defined as: 


A scientist is interested in the effect of time spent with parents and the number of hours youth spend watching television. The researcher knows that the average teen whose parents work outside the home spends 20 hours a week watching television. The population mean = 20 and the standard deviation of the distribution is equal to 5. Calculate the zscores for the following individual times: If X = 5, z = __________. 
3.0 

A scientist is interested in the effect of time spent with parents and the number of hours youth spend watching television. The researcher knows that the average teen whose parents work outside the home spends 20 hours a week watching television. The population mean = 20 and the standard deviation of the distribution is equal to 5. Calculate the zscores for the following individual times: If X = 37, z = __________. 
3.40 

A scientist is interested in the effect of time spent with parents and the number of hours youth spend watching television. The researcher knows that the average teen whose parents work outside the home spends 20 hours a week watching television. The population mean = 20 and the standard deviation of the distribution is equal to 5. Calculate the zscores for the following individual times: If X = 20, z = __________. 
0.00 

Which of the following is NOT true of the normal curve? 
It is skewed. It is a probability distribution. Its total area contains 100% of the cases. The mode, median, and mean are identical. 

The normal curve is: 
a theoretical ideal. applicable to all real life research situations. positively skewed. all of the above. 

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? 
.68 

About 95% of the scores in a normal distribution lie between two standard deviations below the mean AND two standard deviations above the mean. 
True


Fifty percent of the scores fall below the mean in a normal curve. 
True 

Which of the following is NOT true of the normal curve? 
It can be applied to any distribution encountered by a researcher. It helps for interpretation of the standard deviation. It can be used to describe distributions of scores. It can be used to make statements about probabilities. 

A normal curve:

Is a theoretical ideal Can be used to describe distributions Is used in statistics for making decisions All of the above 

A number whose z score is equal to zero is equal to the mean 
True 

A z score does NOT allow for comparison of different scores from different distributions 
False 

The probability of rolling a 4 on one toss of a standard sixsided die is 
.167 .25 .1 1.67 

The probability of rolling a 4 or a 6 is 
.333 .028 .167 .409 

The probability of rolling a 4 on one toss and 6 on the second toss is 
.028 .169 .334 .409 

A z score tells nothing about the distance of a score from the mean 
False 

Which of the following is true of the normal distribution 
Normal distribution is symmetrical The normal distribution is unimodal The tails extend indefinitely in either direction All of the above 

A probability distribution has 
A mean and standard deviation 