2. The following table shows the IQ test scores of some students: IQ test score Frequency 9 50-59 60-69 13 70-79 27 80-89 13 90-99 9. (a) Construct the relative frequency, cumulative frequency and cumulative relative frequency distribution (b) What percentage of students have IQ (c) Find the mean and variance of IQ score of the students. ore under 60?

How was the following relative frequency answers on the bottom left corner found from the data table on the upper right corner?

A psychologist has designed an index to measure the social perspectives of elementary school children. The index is based on ratings of a child’s responses to questions about a set of photographs showing different social situations.  The following are the indices measured on a random sample of 16 children attending elementary school in a particular district.   48, 75, 69, 58, 60, 68, 59, 66, 71, 52, 49, 60, 54, 55, 70, 57   For the data the mean index is 60.69 and the standard deviation is 8.26. The confidence interval is 95%, with a level of significance of 0.05. Perform a statistical test to determine if the population mean index is greater than 50. a) Name of hypothesis test:   b) H0:   c) HA:   d) Test Statistic:   e) Rejection region:   f) Decision in the context of the problem:

The durations (minutes) of 26 electric power outages in the community of Sonando Heights over the past five years are shown below.    38 48 22 69 24 15 53 14 48 1 13 42 42 99 30 18 12 53 19 2 17 26 93 25 16 20           Click here for the Excel Data File (a) Find the mean, median, and mode. (Round your answers to 2 decimal places.)     Descriptive Statistics Data   Mean     Median     Mode        (b) Are the mean and median about the same?    (Click to select)   Yes   No  , the mean is   (Click to select)   greater than   less than  the median. (c) Is the mode a good measure of center for this data set?   Yes No  (d) Is the distribution skewed?   Yes, the distribution is skewed left. No, the distribution is symmetric. Yes, the distribution is skewed right.