Question

Students will follow the hypothesis testing steps for each problem. They will compute the problem using the SPSS program. They will write the results in appropriate APA format and interpret the results. Steps of hypothesis testing will be typed out in a word document, as well as a copy and paste of the SPSS output.

For the following problems, you will:

• Do all steps of hypothesis testing
  • Populations and hypotheses
  • Write out the steps you would do to calculate t
  • Choose the t-cutoff score
  • Calculate the t-statistic using the computer program SPSS
  • Write the t-statistic using proper APA format
  • Decide whether or not you would reject the null hypothesis
• Interpret this result
• Be sure to include a copy of the SPSS output in the word document

1. Single Sample T-test

A researcher would like to study the effect of alcohol on reaction time. It is known that under regular circumstances the distribution of reaction times is normal with μ = 200. A sample of 10 subjects is obtained. Reaction time is measured for each individual after consumption of alcohol. Their reaction times were: 219, 221, 222, 222, 227, 228, 223, 230, 228, and 232. Use α = 0.05.

Answer 1

Given that,
population mean(u)=200
sample mean, x =225.2
standard deviation, s =4.341
number (n)=10
null, Ho: μ=200
alternate, H1: μ!=200
level of significance, α = 0.05
from standard normal table, two tailed t α/2 =2.262
since our test is two-tailed
reject Ho, if to < -2.262 OR if to > 2.262
we use test statistic (t) = x-u/(s.d/sqrt(n))
to =225.2-200/(4.341/sqrt(10))
to =18.357
| to | =18.357
critical value
the value of |t α| with n-1 = 9 d.f is 2.262
we got |to| =18.357 & | t α | =2.262
make decision
hence value of | to | > | t α| and here we reject Ho
p-value :two tailed ( double the one tail ) - Ha : ( p != 18.3574 ) = 0
hence value of p0.05 > 0,here we reject Ho
ANSWERS
---------------
null, Ho: μ=200
alternate, H1: μ!=200
test statistic: 18.357
critical value: -2.262 , 2.262
decision: reject Ho
p-value: 0
we have enough evidence to support the claim that under regular circumstances the distribution of reaction times is normal with μ = 200