Math Problem / Homework 4

Introductory Biobehavioral Statistics (PSY 204)

Know how to use the following, these will be the equations I give you on Exam 4:

tobt= (X ¯obt-µ)/v(SSX/((N)(N-1))) tobt= (X ¯obt-µ)/s_x ¯

tobt= (D ¯obt-µ_D)/v(SSD/(N)(N-1) )

tobt= ((X ¯1-X ¯2)-µ_(x ¯_1 ?-x ¯?_2 ))/v((SS1+SS2)/(n)(n-1) ) tobt= ((X ¯1-X ¯2))/v(sw2(1/n1+1/n2) )

? ^2= (t_obt 2-1)/(t_obt 2+N-1)

N = n1+n2+n3+…nk

dfT = dfW + dfB

dfT=(N – 1)

dfW= (N – k)

dfB= (k – 1)

SSW= ?¦X2 -[(?¦X1)2/n1+(?¦X2)2/n2+(?¦X2)2/n3+?+(?¦Xk)2/nk]

SSB=[ (?¦X1)2/n1+(?¦X2)2/n2+(?¦X3)2/n3+?+(?¦Xk)2/nk]- (?¦X)2/N

sB2= SSB/dfB

sW2= SSW/dfW= SS

BFobt= sB2/sW2

W

?^2= SS_B/SS_T

? ^2= (SS_B-(k-1)sw2)/(SS_T+ sw2)

For each of the following, (1) indicate the appropriate statistical test and equation, (2) state the null and alternative hypotheses, (3) evaluate your obtained statistic using the correct DF and checkwhether you reject or retain the null hypothesis, and (4) if the result is significant, give a measure of the size of the effect. (5) Answer the question.

President Shalala is interested in whether statistics classes at UM are better than those at FSU and UF. For the last five years, public schools have given students a proficiency test and students score and average of 78. Shalala gives a random sample of 41 PSY 204 students the same test and they score an average of 83 with a standard deviation of 12.2. Use a = 0.052 tail.

(1) Statistical test:

Equation:

(2) H0:

H1:

(3) Obtained statistic:

Critical statistic:

DF:

Conclusion:

?Reject ? Retain

(4) Effect size:

(5) Are statistics classes at UM significantly better than those at FSU, UF, and other public schools and if so, what’s the magnitude of the effect?

In the 1930s, a researcher employed in Atlantic City, New Jersey believed that due to the legalization of alcohol, people missed more work days because they experienced more hangovers. People historically missed a mean of 14 days. To test the hypothesis, the researcher measured the days of work missed in a random sample of 12 people and obtained the following data: 24, 40, 29, 32, 33, 25, 15, 22, 18, 25, 16, 27. Use a = 0.052 tail.

(1) Statistical test:

Equation:

(2) H0:

H1:

(3) Obtained statistic:

Critical statistic:

DF:

?Reject ?Retain

(4) Effect size:

(5) Didpeople in the 1930s miss more work days because they experienced more hangovers due to the legalization of alcohol?

You are curious as to whether new episodes of AMC shows airing have an effect on class attendance. To test this hypothesis, you measures the number of classes of a random sample of 80 students attends the day after no new episodes air and the day after episodes of Breaking Bad air. Can you conclude that students come to class less after new episodes air? Use a = 0.052 tail.

(1) Statistical test:

Equation:

(2) H0:

H1:

(3) Obtained statistic:

Critical statistic:

DF:

? Reject ? Retain

(4) Effect size:

(5) Do new episodes of AMC shows airing have an effect on class attendance and if so, what’s the magnitude of the effect?

You are trying to decide between purchasing an iPhone and an Andriod cell phone. One factor that is important to you is battery life. You find six friends who have an iPhone, and six other friends who have an Android, and ask them to record the number of hours their cell phone lasts before the battery is completely drained. The results are below. Use a = 0.052 tail. Hint: If you took Quiz 10, this should look familiar.

iPhone Android

29 16

25 23

17 16

31 17

24 21

21 18

(1) Statistical test:

Equation:

(2) H0:

H1:

(3) Obtained statistic:

Critical statistic:

DF:

? Reject ? Retain

(4) Effect size:

? Yes ? No

(5) Do you decide to purchase an iPhone and an Andriod cell phone?

Oprah notices that women seem more emotional than men and wonders if women remember emotional details better than men. She designs an experiment in which she shows eight men and eight women The Notebook and then asks them to recall as many details as possible about the movie one week later. One man walked out of the movie half way through and did not complete the study. The results are below. Use a = .052 tail.

Men Women

75 85

85 92

67 78

77 80

83 88

88 94

86 90

89

(1) Statistical test:

Equation:

(2) H0:

H1:

(3) Obtained statistic:

Critical statistic:

DF:

? Reject ? Retain

(4) Effect size:

? Yes ? No

(5) Do women remember emotional details better than men?

You want to determine the effect of TV channel on commercial airtime, for four channels: ABC, NBC, FOX, and CBS. You study five one-long timeslots for each channel, and record the commercial airtime in minutes. The results are below. Use a = 0.011tail.

(1) Statistical test:

Equation:

(2) H0:

H1:

(3) Obtained statistic:

Critical statistic:

DF:

? Reject ? Retain

(4) Effect size:

(5) Does at least one channel’s commercial airtime differ from another channel’s commercial airtime and if so, what is the magnitude of the effect?