# Frequency Histogram and Proportion

In a relative frequency histogram for a large set of GPAs, the mean and the standard deviation are 2.10 and 0.21 respectively. What proportion of GPAs falls within 1.68 and 2.52? What about the proportion of measurements that are at most 1.89? Discuss how you arrived at these results.

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#### Solution Summary

This solution calculates the probability of the GPAs falling within 1.68 and 2.52 and the proportion of measurements are at most 1.89 using the mean and standard deviation. All steps are shown in an Excel file with full formulas.

How to make distribution table, histogram, stem and leaf plot? How to calculate percentiles?

1.) A researcher has been measuring the time for pairs of 8 year olds who have just met each other to work together to solve a problem. Using the following set of times to first disagreement (minutes) for each pair to answer the following questions:

scores: 30, 33, 40, 37, 32, 33, 40, 41, 34, 40, 31, 34, 34, 39, 37, 40, 35, 41, 41, 40.

a. Construct a distribution table for these data. include the colums and values for proportion and percentage.

b. Construct a frequency distribution histogram graph for the data.

c. Construct a stem and leaf plot for these data.

2.) Dr. I.C. Ewe has collected reaction times (in seconds) for an eye tracking test with individuals who have been given an experimental drug. your job is to organize the data for Dr. EWE.

Reaction times: 15, 51, 59, 41, 43, 33, 64, 78, 46, 38, 52, 47, 57, 54, 41, 20, 66, 45, 32, 37.

a. Construct a frequency distribution table for these data. Be sure to explain your selection of a tabular vs. grouped distribution table. Include in your table columns for proportion and percent.

b. Draw graph of these data. Be sure to explain your selection of the type of graph you use.

c. Construct a table with cf and c%

d. What scores has a percential rank of 60%?

e. What score has a percentile rank of 50%?

f. What is the percentile rank for X= 45?

g. What is the percentile rank for X= 32?