**Question**

Suppose an automotive repair company wants to determine the current percentage of customers who keep up with regular vehicle maintenance. How many customers should the company survey in order to be 90% confident that the estimated (sample) proportion is within 2 percentage points of the true population proportion of customers who keep up with regular vehicle maintenance?

z0.10 | z0.05 | z0.025 | z0.01 | z0.005 |

1.282 | 1.645 | 1.960 | 2.326 | 2.576 |

Use the table of values above.

**Question**

Suppose a clothing store wants to determine the current percentage of customers who are over the age of forty. How many customers should the company survey in order to be 92% confident that the estimated (sample) proportion is within 3 percentage points of the true population proportion of customers who are over the age of forty?

z0.16 | z0.08 | z0.04 | z0.02 | z0.01 |

0.994 | 1.405 | 1.751 | 2.054 | 2.326 |

Use the table of values above.

**Question**

Suppose a shoe store wants to determine the current percentage of customers who are males. How many customers should the company survey in order to be 98% confident that the estimated (sample) proportion is within 3 percentage points of the true population proportion of customers who are males?

z0.10 | z0.05 | z0.025 | z0.01 | z0.005 |

1.282 | 1.645 | 1.960 | 2.326 | 2.576 |

Use the table of values above.

**Question**

Suppose an automotive repair company wants to determine the current percentage of customers who keep up with regular vehicle maintenance. How many customers should the company survey in order to be 95% confident that the estimated (sample) proportion is within 2 percentage points of the true population proportion of customers who keep up with regular vehicle maintenance?

z0.10 | z0.05 | z0.025 | z0.01 | z0.005 |

1.282 | 1.645 | 1.960 | 2.326 | 2.576 |

Use the table of values above.

# Solution:

Suppose an automotive repair company wants to determine the current percentage of customers who keep up with regular vehicle maintenance. How many customers should the company survey in order to be 90% confident that the estimated (sample) proportion is within 2 percentage points of the true population proportion of customers who keep up with regular vehicle maintenance?

z0.10 | z0.05 | z0.025 | z0.01 | z0.005 |

1.282 | 1.645 | 1.960 | 2.326 | 2.576 |

Use the table of values above.

**Answer**: 1692

Suppose a clothing store wants to determine the current percentage of customers who are over the age of forty. How many customers should the…**Please click the icon below to download at $3**