Data Visualization

1.What would suggest that a dataset is not normal?

(a)The plot layer geom_histogram is showing observations that are narrowly distributed about the mean

(b)The ggplot layergeom_jitter () is showing large number of outliers

(c)The median () is several magnitudes smaller than the mean ()

(d)The summary () function is showing the first quartile is smaller than the third quartile

2.If the age in the class is approximately normally distributed, and if the mean age of a student is 28 with a standard deviation of 4, what proportion of the student would be between24 and 32?

(a)0

(b)68

(c)75

(d)95

3.The geom_boxplot layer from the ggplot2R package will dis-play a box that starts at

(a)the lowest value in the data

(b)the highest value in the data

(c)the first quartile

(d)the median

4.The geom_boxplot layer from the ggplot2R package is derived from

(a)the mean

(b)the median

(c)the quartiles

(d)all or the above

5.The geom_boxplot layer from the ggplot2R package is a

(a)visual presentation of quartiles

(b)numerical presentation of quartiles

(c)numerical computation of the standard deviation

(d)simple plot showing the mean, median and mode

6.In a normal distribution, what proportion of the observations are within two standard deviations of the mean?

(a)50

(b)95

(c)68

(d)99.77.

7.Which of the following is true about the median statistic in R?

(a)It is affected by extremely large or small values, and should therefore be avoided.

(b)To find the median, R users need to enter multiple lines of code in order to figure out the value.

(c)It is the value that occurs most often, and requires the use of loops.

(d)It can be computed very easily in R with the function median ()

8.The geom_histogram and the geom_boxplot layer from thegg-plot2R package could

(a)help determine if a continuous variable is normal

(b)determine the relation between two variables

(c)not be used for continuous data

(d)create confusion when exploring a new data set

9.When the R sd () function outputs the value -2.5, you conclude that

(a)the mean is greater than the median

(b)the median is greater than the mean

(c)the dispersion in the data is low

(d)this question is misleading

10.The geom_histogram layer from the ggplot2R package has large gaps between the bars.

(a)True

(b)False