Margin of error from a standard error

z * se, the half-width of a confidence interval. The default z = 1.96 gives an approximate 95% interval; the survey reports used the 2 * se rule of thumb, which is z = 2.

Usage

margin_of_error(se, z = 1.96)

Arguments

se

A standard error (scalar or vector).

z

The critical value / multiplier. Defaults to 1.96 (95%). Use 2 to reproduce the report's rule of thumb.

Value

The +/- margin of error, on the same scale as se.

Details

A confidence interval is the estimate plus or minus this margin. z = 1.96 gives the standard 95% interval; z = 2 reproduces the "two standard errors" rule of thumb often quoted in survey reports; z = 2.58 gives 99%. The result is on the same scale as se, so for a proportion error in percentage points, pass se_prop(p, n, pctp = TRUE).

See also

se_mean(), se_prop(), diagnose().

Other diagnostics: diagnose(), precision_summary(), rse(), rse_rating(), se_mean(), se_prop()

Examples

margin_of_error(se_prop(0.33, 1184, pctp = TRUE))   # in percentage points
#> [1] 2.678395

margin_of_error(0.02, z = 2)
#> [1] 0.04