Home Chapter 5 Quiz

# Quiz

This activity contains 15 questions.

## Continuous variables differ from discrete variables in that:

 probabilities can be obtained by cumulating an area under a curve. All of the choices are correct. any value within the range of the variable can occur, rather than just specific values. the probability of occurrence of a specific value X is zero.

## If a value is equally likely to occur anywhere in the range between the smallest value of a and the largest value b, the data follows a __________.

 Weibull distribution uniform distribution bell curve sampling distribution

## The normal distribution is important in statistics because:

 it can be used to approximate numerous phenomena measured on a continuous scale. it can be used to approximate discrete probability distributions. it provides the basis for classical statistical inference. All of the choices are correct.

## The ability to transform a value to a(n) ________________ allows statisticians to use one table for all normally distributed random variables.

 standard normal score probability frequency average

## The graphical method for evaluating whether a particular variable is approximately normally distributed is the normal __________ plot.

 distribution frequency standard probability

## If a right skewed variable is transformed using natural logarithms and the transformed values are normally distributed, the result is a ____________ distribution.

 left-skewed Weibull Poisson lognormal

## A variable follows an exponential distribution and is known to have a standard deviation of 12, give the mean.

 12 3.5 144 0.08

## The standard deviation of the sampling distribution of the mean is also referred to as the __________.

 sum of squares standard error of the mean variance None of the choices are correct.

## If 25 samples of 30 observations are drawn from a left-skewed population, the resulting sampling distribution of the mean will:

 be left skewed. be approximately normal. possibly be right skewed. possibly be normal but mostly likely left skewed.

## Given a sampling distribution of a proportion with a mean of 0.15, for a constant sample size of 50, find the standard normal score for the sample proportion of .

 1.24 0.64 2.86 0.99

## A statistician has found that the amount of rainfall a specific region receives in a year follows an exponential distribution with a mean of 22. What is the probability that the region will receive less than 20 inches of rain next year?

 0.597 0.423 0.184 0.367

## A variable is exponentially distributed. The probability that is 68.33%. Calculate the variance for the distribution.

 4.35 1.34 8.09 2.94

Suppose a researcher wants to determine the interval around the mean of a population (, ) that would include the middle 95 percent of the means based on samples of . Give the interval.

 (27.81, 32.19) (28.25, 31.75) (29.46, 30.54) (27.14, 32.86)

## Given that a variable is uniformly distributed between 1146.7 and 5213.4, calculate the expected value.

 3180 1194 4375 2946

## For a ___________ plot, the ordered array of observed scores and the z scores of a normally distributed variable will yield a straight line.

 quantile-quantile frequency distribution box-and-whisker normal probability