Please answer all parts for the following question: A) Identify the independent

Question

Please answer all parts for the following question:

A) Identify the independent and dependent variables.

B) State the null and alternative hypothesis (both in words specific to the particular study and in symbols).

C) Determine the critical value (use alpha = .05).

D) Calculate the t-statistic and all the required intermediate steps.

E) Make a correct decision regarding the null hypothesis & provide a short conclusion (i.e., how the IV affects the DV).

F) Calculate a measure of effect size – Cohen’s d.

G) Determine which error is possible based on your decision (Type I or Type II).

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Alcohol is a legal drug in most countries once an individual reaches a certain age; however, the effects of long term alcohol consumption on one's intelligence has gone relatively untested. The average intelligence of a person is known to be µ = 100, but a group of researchers at the local University believe that chronic alcohol consumption might lower one's intelligence below the average. To test this hypothesis they randomly select 100 college seniors and have them participate in an experiment where they must get drunk in various situations every Friday and Saturday for the next 15 years. Afterwards, each participant is forced into a month of sobriety and then given an IQ test. The average IQ score for the 100 participants is M = 96 with a standard deviation of s = 15.

Explanation / Answer

Given that,
population mean(u)=100
sample mean, x =96
standard deviation, s =15
number (n)=100
null, Ho: =100
alternate, H1: <100
level of significance, = 0.05
from standard normal table,left tailed t /2 =1.66
since our test is left-tailed
reject Ho, if to < -1.66
we use test statistic (t) = x-u/(s.d/sqrt(n))
to =96-100/(15/sqrt(100))
to =-2.667
| to | =2.667
critical value
the value of |t | with n-1 = 99 d.f is 1.66
we got |to| =2.667 & | t | =1.66
make decision
hence value of | to | > | t | and here we reject Ho
p-value :left tail - Ha : ( p < -2.6667 ) = 0.00447
hence value of p0.05 > 0.00447,here we reject Ho
ANSWERS
---------------
null, Ho: =100
alternate, H1: <100
test statistic: -2.667
critical value: -1.66
decision: reject Ho
p-value: 0.00447
we have evidence that chronic alcohol consumption might lower one's intelligence below the average.

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