Chapter 5: Continuous Random Variables
Quiz 1



1.  

All of the following are characteristics of the normal curve except:



2.  

Normal curve IQ scores are normally distributed with a mean of 100 and a standard deviation of 16. The probability that a randomly selected person has an IQ less than 116 is:



3.  

All of the following statements are true except:



4.  

The probability that a normally distributed variable x will assume a specific value is:



5.  

The probability distribution that plays the most important role in the science of statistical inference is:



6.  

IQ scores are normally distributed with a mean of 100 and a standard deviation of 16. If x is the random variable representing an IQ score, the probability that x is between 84 and 116, P (84 < x < 116) is:



7.  

A standard normal z score of 1.28 corresponds to approximately what percentile of the standard normal distribution?



8.  

If heights of a certain group of adult males are normally distributed with a mean of 68.2 inches and a standard deviation of 4.1 inches, find the twenty-fifth percentile for this distribution.



9.  

Find the probability that a standard normal variable lies to the left of 0.74.



10.  

The times required to assemble a product part are normally distributed with a mean of 47.5 minutes and a standard deviation of 8.5 minutes. What fraction of the assembly workers require more than one hour?



11.  

IQ scores are normally distributed with a mean of 100 and standard deviation of 16. Determine the false statement from among the statements below:



12.  

All of the following are properties of the normal curve except



13.  

For the normal distribution, what percent of the observations are within plus or minus 1.96 standard deviations?



14.  

One way to determine whether the data are from an approximately normal distribution is:



15.  

Identify the statement below that is false:

Note: answer choices in this exercise are randomized.

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