chap 5 Ap stat

Which of these variables about German Shepherds is most likely to be described by a Normal model?

• age

• breed

• number of days housed in an animal shelter

• weight

forester shows the accompanying histogram of tree diameters he used in analyzing 27 trees in a large woods that was for sale. Was he justified in using a Normal model to analyze the woods? Explain, citing some specific concerns.

• Yes, because the histogram is unimodal and symmetric.

• No, because while the histogram is unimodal, it is not symmetric

• No, because the histogram is not unimodal or symmetric.

• No, because while the histogram is symmetric, it is not unimodal

Which of the following statistics are changed by multiplying each data value by a constant (rescaling)?

• Mean

• Median

• IQR

• Standard deviation

• All of the above

Which of these variables is most likely to follow a Normal model?

• head circumference

• number of cigarettes smoked daily

• hours spent biking in the last week

• eye color

Corey has 4929 songs in his computer's music library. The lengths of the songs have a mean of 242.4 seconds and

standard deviation of 114.51 seconds with the accompanying Normal probability plot of song lengths

Is this distribution Normal? Explain.

• Yes, because the plot is roughly a diagonal straight line.

• Yes, because there is a curved pattern to the plot.

• No, because the plot is not roughly a diagonal straight line.

• No, because there is no pattern to the plot.

Corey has 4929 songs in his computer's music library. The lengths of the songs have a mean of 242.4 seconds and

standard deviation of 114.51 seconds with the accompanying Normal probability plot of song lengths

If it isn't Normal, how does it differ from a Normal model?

• The distribution is skewed to the left.

• The distribution is skewed to the right

• The distribution is uniform

• The plot is Normal

Suppose your statistics professor reports test grades as z-scores, and you got a score of 2.20 on an exam. Write a

sentence explaining what that means.

• The score was 2.20 standard deviations lower than the mean score in the class.

• The score was 2.20 standard deviations higher than the mean score in the class.

• The score was 2.20 points lower than the mean score in the class.

• The score was 2.20 points higher than the mean score in the class

Which of these variables is most likely to follow a Normal model for U.S. adults?

• monthly mortgage

• eye color

• income

• ACT scores

A standardized value is a value found by which of the following?

• Subtracting the mean from the value and then dividing the result by the standard

  deviation of the data set

• Comparing the value with the other values in the data set

• Subtracting the value from the mean of the data set

• Computing the mode

• Dividing the value by the standard deviation of the data set

Suppose that a Normal model describes the acidity (pH) of rainwater, and that water tested after last week's storm had a z-score of + 1.8. What does this mean about the acidity of the rain in last week's storm?

• The rain had a pH 1.8 standard deviations higher than that of average rainwater.

• The rain had a pH of 1.8.

• The rain had a pH 1.8 higher than average rainfall.

• The rain varied with a standard deviation of 1.8.