Question

Dr. Anderson is a mammalogist who studies deer mice. He is trying to improve his success in trapping female deer mice. He conducts a study where he uses peanut butter vs. nutella as bait in his traps. The data he collects is shown in the table below. He is going to use a Chi-Squared test to analyze his results.

Dr. Anderson is a mammalogist who studies deer mice. He is trying to improve his success in trapping female deer mice. He conducts a study where he uses peanut butter vs. nutella as bait in his traps. The data he collects is shown in the table below. He is going to use a Chi-Squared test to analyze his results.

	Trap with Peanut Butter	Trap with Nutella	Total
Females	46	71	117
Males	37	83	120
Total	83	154	237

(a)  Females prefers peanut butter bait over nutella or vice versa would be the   (null or alternate) hypothesis

(b) The expected frequency for females that prefer peanut butter is  (report to 4 decimal places)

(c)   The expected frequency for females that prefer nutella is  (report to 4 decimal places)

(d) The expected frequency for males that prefer peanut butteris  (report to 4 decimal places)

(e) The expected frequency for males that prefer nutella is  (report to 4 decimal places)

(f) degrees of freedom =

(g) The calculated chi-square value =  (report to 4 decimal places)

(i) The critical chi-square value at alpha =0.05 =

(j) Would you reject or fail to reject the null hypothesis?

(k) Would females prefer one type of bait than the other?  (yes or no)

Answer 1

using excel>addin>phstat>muliple sample test >chi square

we have

Chi-Square Test
Observed Frequencies
	Trap with			Calculations
Gender	Peanut Butter	Nuella	Total		fo-fe
Females	46	71	117		5.025316	-5.02532
Males	37	83	120		-5.02532	5.025316
Total	83	154	237
Expected Frequencies
	Trap with
Gender	Peanut Butter	Nuella	Total		(fo-fe)^2/fe
Females	40.97468	76.02532	117		0.616327	0.332176
Males	42.02532	77.97468	120		0.600919	0.323872
Total	83	154	237
Data
Level of Significance	0.05
Number of Rows	2
Number of Columns	2
Degrees of Freedom	1
Results
Critical Value	3.841459
Chi-Square Test Statistic	1.873294
p-Value	0.171098
Do not reject the null hypothesis

(a)  Females prefers peanut butter bait over nutella or vice versa would be the null hypothesis

(b) The expected frequency for females that prefer peanut butter is 40.9747

(c)   The expected frequency for females that prefer nutella is 76.0253

(d) The expected frequency for males that prefer peanut butteris 42.0253

(e) The expected frequency for males that prefer nutella is 77.9747

(f) degrees of freedom =1

(g) The calculated chi-square value = 1.8733

(i) The critical chi-square value at alpha =0.05 =3.8415

(j) no ,you reject or fail to reject the null hypothesis

(k) Yes , females would prefer one type of bait than the other .