Exam 3: Summary Statistics

The standard deviation of a distribution is the

A smaller standard deviation of a distribution indicates that

A scatter diagram is potentially valuable because it

An outlier that is much smaller than the remaining values in a data set will cause the data set to be

The mean is the

A data set is said to be skewed to the left if

-The scatter diagram in figure suggests that ______ relationship likely exists between daily rainfall and the Dow Jones industrial average.

Relative frequency histograms are potentially valuable because they

The correlation coefficient is generally preferred to the covariance because

When is the median most appropriate for summarizing a data set?

If a data set is skewed then

The covariance

Suppose that a data set contains 275 observations ranging from a low of 6,000 to a high of 70,000.What is the appropriate class width to use when constructing a histogram for the data?

A counselor working with teenagers is interested in the relationship between anxiety and depression.The counselor administers a depression and anxiety test to each teenager.The scores obtained from the administration of the two inventories are given below. Anxiety Depression 22 16 12 8 68 33 10 6 5 5 53 24 44 18 37 17 0 2 21 14 64 31 33 17 55 30 18 13 3 3 4 4 11 7 13 9 7 5 The summary statistics are Anxiety Depression Sample mean 25.2632 13.7895 Standard deviation 21.9895 9.8464 $\sum_{i=1}^{19}\left(x_{1}-\bar{x}\right)\left(y_{i}-\bar{y}\right)=3828.0526$ a.What do these data say about the level of anxiety and depression in these teenagers? b.What is the correlation between anxiety and depression? What does this number tell you? c.What is the correlation coefficient between anxiety and depression? What does this number tell you? d.If you were counseling a teenager with high levels of anxiety,what would you expect their level of depression to be?

Suppose that you construct the histogram in Figure What conclusions would you draw about the data? Explain.

a.If the correlation coefficient between two random variables equals zero,does that imply that there is no relationship between those random variables? b.If the correlation coefficient between two random variables is close to one in absolute value,does that imply that one random variable causes another random variable?

-The scatter diagram in figure suggests that ______ relationship likely exists between 30-year mortgage rates and new home sales.

Suppose you have collected the data in Table Table 3.1 2 34 19 5 9 14 25 31 51 22 27 13 14 12 5 21 30 25 15 14 Calculate the mean,median,mode,variance,and standard deviation.Interpret these values.

-The scatter diagram in figure suggests that _______ relationship likely exists between the price and quantity supplied of surfboards.

The standard deviation of a distribution provides a sense of