# σ = 0.40, n = 750 & 95% Confidence Level - Margin of Error Example

Example problem workout with steps & calculation summary for accepted margin of error calculated from *population standard deviation* σ = 0.40, *sample size* n = 750 & 95% confidence level in statistical surveys or experiments.

Calculation Summary | |
---|---|

Standard Deviation (σ) | 0.40 |

Sample Size (n) | 750 |

Confidence Level | 95% |

MOE | 2.86% |

## Work with Steps for σ = 0.40 n = 750 & 95% Confidence Level

__Question:__

A survey was conducted to know the interest of people includes 750 persons with the deviation of interest of people 0.40. What is the acceptable margin of error included in this survey to make the survey statistically significant at 95% confidence level.

__Workout :__

step 1 Address the formula input parameters and values

Standard Deviation (σ) = 0.40

Sample Size (n) = 750

Z value for 95% confidence level = 1.960

MOE = Z σ√n

step 2 Substitute σ , n & Z value in the below margin of error formula

MOE = 1.960 x 0.40√750

step 3 Solve the above expression

MOE = 1.960 x 0.40/27.3861

= 1.960 x 0.0146

= 0.0286 x 100

= 2.86 %

Thus 2.86 % is the Margin of error calculated from σ = 0.40, n = 750 & 95% confidence level.