## PSY 335 Interpreting Statistics Worksheet

# 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
| Verbal IQ |
Rdg. Comp. |
---|---|---|

1
| 90 |
88 |

2
| 99 |
97 |

3
| 101 |
110 |

4
| 115 |
121 |

5
| 97 |
98 |

6
| 98 |
95 |

7
| 92 |
89 |

8
| 104 |
109 |

9
| 103 |
100 |

10
| 117 |
100 |

11
| 100 |
96 |

12
| 98 |
101 |

13
| 96 |
105 |

14
| 105 |
105 |

15
| 78 |
80 |

16
| 121 |
99 |

17
| 82 |
75 |

18
| 85 |
89 |

19
| 81 |
78 |

20
| 82 |
86 |

MEAN
| 97 |
96 |

MEDIAN
| 98 |
97 |

MODE
| 98 |
89 |

STD.DEV.
| 11.8 |
11.2 |

RANGE
| 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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