A researcher would like to examine how the chemical tryptophan,contained in foods such as turkey, can affect mental alertness. Asample of n = 8 college students is obtained, and each student’sperformance on a familiar video game (total points earned in thegame) is measured before and after eating a traditionalThanksgiving dinner including roast turkey. The following table arethe scores for each participant before and after the meal:

Participants: 1,2,3,4,5,6,7,8,

Before Meal (X1): 220,245,215,260,300,280,250,310

After Meal (X2) 210,220,195,265,275,290,220,285

a.For a two-tailed test, what is the null hypothesis usingstatistical notation?

b. For a two-tailed test, what is the alternative hypothesisusing statistical notation?  

c. What is the sum of the difference scores (D)?

d. What is the value of MD?

e. What is the value for Sum of Squares for the differencescores (SSD)?

f. What is the sample variance for the difference scores (sD 2)?

g. What is estimated standard error (sMD)?

h. For a two-tailed test with α = .05, what is the value/s fortcrit?

i. What is the value for tobt?  

j. Do these data indicate a significant difference between thetreatments at the .05 level of significance? NOTE: simply writingthat the effect is significant (e.g., only writing “reject thenull”) without showing any work/calculations in parts a-e willresult in point zero points.

k. Compute estimated Cohen’s d to measure the size of thetreatment effect.