Question

- A sample of grade point averages was recently taken from a
group of individuals who recently passed the California Bar Exam.
The results were: 3.06, 3.56, 3.20, 2.87, 3.3, 3.61, 3.75, 3.1, 4,
3.65.
- Find the sample mean and sample standard deviation for these results.
- Find the 95% confidence interval for the mean G.P.A. of students who pass the California Bar Exam.
- Suppose that another sample was taken of 30 people who recently passed the California Bar Exam, and the mean and standard deviation for the G.P.A.s in this group were the same as those that you calculated in part (a) above. Find the 95% confidence interval for the mean G.P.A. of students who pass the California Bar Exam.

Answer #1

Data | ||

3.06 | ||

3.56 | ||

3.2 | ||

2.87 | ||

3.3 | ||

3.61 | ||

3.75 | ||

3.1 | ||

4 | ||

3.65 | ||

a) Mean |
3.41 | |

SD |
0.357491 | |

n | 10 | |

b) 95%CI |
alpha | 0.05 |

df | 9 | n-1 |

tc | 2.262157 | |

Lower | 3.154266 | Mean-tc*SD/SQRT(n) |

Upper | 3.665734 | Mean+tc*SD/SQRT(n) |

c) 95% CI |
alpha | 0.05 |

df | 29 | n-1 |

tc | 2.04523 | |

Lower | 3.276511 | Mean-tc*SD/SQRT(30) |

Upper | 3.543489 | Mean+tc*SD/SQRT(30) |

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