Question

As part of the study on ongoing fright symptoms due to exposure to horror movies at a young age, the following table was presented to describe the lasting impact these movies have had during bedtime and waking life:

		Waking symptoms
Bedtime symptoms		Yes		No
Yes		35		32
No		34		18

(a) What percent of the students have lasting waking-life symptoms? (Round your answer to two decimal places.)
%

(b) What percent of the students have both waking-life and bedtime symptoms? (Round your answer to two decimal places.)
%

(c) Test whether there is an association between waking-life and bedtime symptoms. State the null and alternative hypotheses. (Use α = 0.01.)

State the χ² statistic and the P-value. (Round your answers for χ² and the P-value to three decimal places.)

χ2	=
df	=
P	=

Answer 1

Ans:

a)

Percent of the students have lasting waking-life symptoms=100*69/119=57.98%

b)

percent of the students have both waking-life and bedtime symptoms=100*35/119=29.41%

c)

	Observed freq.(fo)
	walking symptoms
Bedtime sym.	Yes	No	Total
Yes	35	32	67
No	34	18	52
Total	69	50	119
	Expected freq.(fe)
	walking symptoms
Bedtime sym.	Yes	No	Total
Yes	38.85	28.15	67
No	30.15	21.85	52
Total	69	50	119
	Chi square=(fo-fe)^2/fe
	walking symptoms
Bedtime sym.	Yes	No	Total
Yes	0.381	0.526	0.907
No	0.491	0.678	1.169
Total	0.873	1.204	2.077

Chi square=2.077

df=(2-1)*(2-1)=1

p-value=CHIDIST(2.077,1)=0.150

As,p-value>0.01,we fail to reject the null hypothesis.

There is not sufficient evidence to conclude that  there is an association between waking-life and bedtime symptoms.