using the zchart I came up with this so far

70+- 1.960(17.50/v-10) (square root of 10)

somehow this is not right, 1.960 should actually be 2.262 and I'm not sure how, any help would be appreciated.

- Thread starter sinful
- Start date

using the zchart I came up with this so far

70+- 1.960(17.50/v-10) (square root of 10)

somehow this is not right, 1.960 should actually be 2.262 and I'm not sure how, any help would be appreciated.

sinful said:

also, if my sample size was say 20 which would be (dof 19) it would have been 2.093?

sinful said:

One other question, why would the chart go above 30 if you would use the z if the sample size was greater than 30? Thank you so much for your help btw, I've been trying to figure htis out the past couple hours