Question

xcel Online DATAfile Activity: Twins

In Born together—Reared apart: the Landmark Minnesota twin study (2012), Nancy Segal discusses the efforts of research psychologists at the University of Minnesota to understand similarities and differences between twins by studying sets of twins who were raised separately. The Excel Online file below contains critical reading SAT scores for several pairs of identical twins (twins who share all of their genes), one of whom was raised in a family with no other children (no siblings) and one of whom was raised in a family with other children (with siblings). Construct a spreadsheet to answer the following questions.

Open spreadsheet

Change in SAT Score (di)
Mean	-9.9
Standard Error	15.4527974
Median	-25.5
Mode	-46
Standard Deviation	69.10701084
Sample Variance	4775.778947
Kurtosis	-1.028710457
Skewness	0.155949652
Range	242
Minimum	-121
Maximum	121
Sum	-198
Count	20
Largest(1)	121
Smallest(1)	-121
Confidence Level(90%)	26.71993871

Part b			Formula
The 90% confidence interval
C.I.Lower Limit	-36.62		=F4-F19
C.I.Upper Limit	16.82		=F4+F19
Part c
Degrees of Freedom	19		=F16-1

a. What is the mean difference between the critical reading SAT scores for the twins raised with no siblings and the twins raised with siblings?

-9.9 (to 2 decimals)

b. Provide a 90% confidence interval estimate of the mean difference between the critical reading SAT scores for the twins raised with no siblings and the twins raised with siblings.

(-36.62,16.82) (to 2 decimals)

c. Conduct a hypothesis test of equality of the critical reading SAT scores for the twins raised with no siblings and the twins raised with siblings.

p-value is?

Hello, could someone please tell me what the p value is? idk how to get it and these are all the informations possible

Answer 1

c.

p-value:

Test statistic for paired samples t-test is:

t = = -9.9/15.45 = - 0.641

(where, S.E =Standard Error =​​​​​ =15.45 where n=sample size =20 and s =Std.deviation =69.107: given).

Degrees of freedom, df =n-1 =20-1 =19

At df =19, for two-tailed test, p-value for the test statistic of t = - 0.641 is: p-value =0.529

This can be calculated using online tools or excel by entering test statistic value, df and number of tails (1 or 2).

In Excel, enter test statistic of 0.641 instead of -0.641 (p-value is same for both of them).

Excel formula: =tdist(test statistic, df, tails)

That is, =tdist(0.641, 19, 2) and press "Enter" button.

This gives the answer: 0.529