Mba 510 Applied Statistical Methods

Concordia University Wisconsin

Master of Business Administration

Contents Page

Question 1

Dr. Susan Benner is an industrial psychologist. She is currently studying stress

among executives of Internet companies. She has developed a questionnaire that

she believes measures stress. A score above 80 indicates stress at a dangerous level.

A random sample of 15 executives revealed the following stress level scores.

94 | 78 | 83 | 90 | 78 | 99 | 97 | 90 | 97 | 90 | 93 | 94 | 100 | 75 | 84 |

a. Find the mean stress level for this sample. What is the point estimate of the population mean?

Answer a:

Descriptive statistics | |

| |

　 | stress |

count | 15 |

mean | 89.47 |

sample variance | 65.27 |

sample standard deviation | 8.08 |

minimum | 75 |

maximum | 100 |

range | 25 |

The mean stress level for this sample is 89.47

The point estimate of the population mean is also 89.47

b. Construct a 95 percent confidence level for the population mean.

Answer b:

Confidence interval - mean |

confidence level | 95% |

mean | 89.47 |

std. dev. | 8.08 |

n | 15 |

t (df = 14) | 2.145 |

half-width | 4.475 |

upper confidence limit | 93.945 |

lower confidence limit | 84.995 |

According to the calculation in question a, the upper confidence limit is 93.945 and the lower confidence limit is 84.995. Since sample mean is 89.47. Hence, it cannot represent population mean.

c. Is it reasonable to conclude that Internet executives have a mean stress level in the dangerous level, according to Dr. Benner’s test?

Answer c:

According to Dr. Susan Benner, a score of above 80 would indicate stress at a dangerous level. We find that lower confidence limit is 84.995, the lowest level is over 80. We can conclude that internet executives have a mean stress level in a dangerous level.

Question 2

According to the Coffee Research Organization...