Why is it significantly different What makes two numbers hav

Why is it significantly different?

What makes two numbers have significant difference?

I don\'t get it.

Stat. sucks...

(19.58 S-AQ) Healthy women aged 18 to 40 participated in a study of eating habits. Subjects were given bags of potato chips and bottled water and invited to snack freely. Interviews showed that some women were trying to restrain their diet out of concern about their weight. How much effect did these good intentions have on their eating habits? Here are the data on grams of potato chips consumed (note that the study report gave the standard error of the mean rather than the standard deviation) Group Unrestrained Restrained SEM 6.23 10 2 64.89 31 The standard error of the difference of sample means0.0001) is: 11.7819 The critical value (±0.001) from the t distribution for confidence interval 80% using the conservative degrees of freedom is f* = 1.397 Give a 80% confidence interval ( 0.01) that describes the effect of restraint 17.43 to Based on this interva is there a significant difference batween the two groups? . Yes

Solution

Here significance means statistical significance, i.e., that the difference in two groups was such that it must not have occured by purely chance. Here, we look at the confidence interval, and note that this 80% CI does not contain zero, which imples that the true mean difference should not be zero, or \"true mean difference is significantly different from zero\" or in other words, that there is a significant difference between means of two groups.

Note: typically we look at p-value, if p-value is smaller than alpha, the result is \"significant\"