# What is the formula for measuring the confidence interval?

**Solution:**

Confidence Interval is used to describe the uncertainty associated with a sampling method

A confidence interval gives the probability within which the true value of the parameter will lie.

Condition | Confidence Interval Formulas |
---|---|

If n ≥ 30 | Confidence Interval = x̄ ± z_{c}(σ/√n) |

If n<30 | Confidence Interval = x̄ ± t_{c}(S/√n |

n = Number of terms

Where,

- x̄ = Sample Mean
- σ = Standard Deviation
- z
_{c}= Value corresponding to confidence interval in z table - t
_{c}= Value corresponding to confidence interval in t table

A confidence interval gives the probability within which the true value of the parameter will lie. The confidence level (in percentage) is selected by the investigator. The higher the confidence level is the wider is the confidence interval (less precise).

Therefore, the formula for measuring the confidence interval is x̄ ± t_{c }(S/√n).

## What is the formula for measuring the confidence interval?

**Summary:**

The formula for measuring the confidence interval is x̄ ± t_{c }(S/√n).

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