Question

A soil scientist has just developed a new type of fertilizer and she wants to determine whether it helps carrots grow larger. She sets up several pots of soil and plants one carrot seed in each pot. Fertilizer is added to half the pots. All the pots are placed in a temperature-controlled greenhouse where they receive adequate light and equal amounts of water. After two months of growth, the scientist harvests the carrots and weighs them (in kilograms). Below is a data table showing the weight of the carrots at the end of the growing period from the two treatment groups.

Sample ID	Control	Fertilizer Treatment
1	0.363	0.202
2	0.414	0.663
3	0.423	0.298
4	0.243	0.849
5	0.429	0.314
6	0.376	0.416
7	0.205	0.39
8	0.211	0.674
9	0.367	0.472
10	0.251	0.674
11	0.462	0.764
12	0.485	0.301
13	0.218	0.183
14	0.307	0.291
15	0.49	0.499
16	0.473	0.273
17	0.262	0.373
18	0.49	0.493
19	0.398	0.765
20	0.358	0.549
21	0.222	0.607
22	0.281	0.265
23	0.422	0.365
24	0.232	0.85
25	0.437	0.511
26	0.405	0.627
27	0.422	0.661
28	0.285	0.611
29	0.283	0.672
30	0.466	0.371

When analyzing this dataset with a t-test, the

___________ hypothesis states that the average size of the carrots from each treatment are the same, whereas the ____________ hypothesis states that the fertilized carrots are larger in size.

To analyze this data set, should the scientist use a __________-tailed t-test?

After performing a t-test assuming equal variances using the data analysis add-in for MS Excel, what is the calculated t-value for this data set? ____________

Round your answer to four decimal places.

Your answer should be a positive value.

Report the appropriate critical t value, based on your decision of a one- or two-tailed test, calculated by MS Excel using the Data Analysis add-in. _____________

Round your answer to four decimal places.

What is the appropriate p value for the t-test? ____________

Report your answer in exponential notation

Report your answer to 4 decimal places after converting to exponential notation

e.g.

1.1234E-01 for 0.112341

3.1234E-04 for 0.000312341

Would you reject or fail to reject the null hypothesis? ___________

Answer 1

When analyzing this dataset with a t-test, the

______Null_____ hypothesis states that the average size of the carrots from each treatment are the same, whereas the __Alternative__________ hypothesis states that the fertilized carrots are larger in size.

To analyze this data set, should the scientist use a __right________-tailed t-test.

Go to data>Data analysis> T test assuming unequal variances

output is

t-Test: Two-Sample Assuming Unequal Variances
	Fertilizer Treatment	Control
Mean	0.499433	0.356
Variance	0.037758	0.00931
Observations	30	30
Hypothesized Mean Difference	0
df	42
t Stat	3.621159
P(T<=t) one-tail	0.000392
t Critical one-tail	1.681952
P(T<=t) two-tail	0.000783
t Critical two-tail	2.018082

t=what is the calculated t-value for this data set?

t=3.6212

Report the appropriate critical t value, b

t crit=1.682

What is the appropriate p value for the t-test? ______

p=0.0004

p<0.05

Would you reject or fail to reject the null hypothesis?

Reject the null hypothesis.