# PSY 335 Interpreting Statistics Worksheet

Testing of 20 randomly selected subjects yielded two sets of scores: Verbal IQ and Reading Comprehension. The table below displays the results and descriptive statistics, as well as frequency distribution charts for each variable and a scatterplot of the correlations between the two variables:

Subject 1 Verbal IQ Rdg. Comp. 90 88 99 97 101 110 115 121 97 98 98 95 92 89 104 109 103 100 117 100 100 96 98 101 96 105 105 105 78 80 121 99 82 75 85 89 81 78 82 86 97 96 98 97 98 89 11.8 11.2 43 46 0.79

Please answer the following questions within the appropriate column in the table below:

 I. Using the provided data and graphs, describe the frequency distribution for the IQ test:What is a typical score for this sample? How variable are the scores? How are the scores distributed? Typical score for this test is 98. The difference between the maximum and minimum values is 43. II. Using the provided data and graphs, describe the frequency distribution of the reading test scores:What is a typical score for this sample? How variable are the scores? How are the scores distributed? Typical score for this test is 89. The difference between the maximum and minimum values is 46. III. Consider the correlation data given the provided data and graph:How are IQ and reading achievement related? The correlation between the two is 0.79 which means there is a positive correlation between IQ and reading achievement. As IQ goes up, reading achievement also goes up. IV. Evaluate the data from a psychological testing perspective: Are these samples good representations of the general population? How do you know?What could you do to make them a more representative sample? How would you interpret the correlation results? What are some ways this knowledge of their relationship could be used? For this it is necessary to know the population parameters. Generally larger the sample less is the risk of a non-representative sample. The smaller the sample, the higher the risk. Here, we can say that the correlation between the two is 0.79 which means there is a positive correlation between IQ and reading achievement. As IQ goes up, reading achievement also goes up.

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