Question

With increases in obesity rates over the past several decades, health care providers have become concerned about the effects of obesity on health. As a health psychologist, you are interested in people’s perceptions and responses to food as this might influence obesity. You are curious if people that are impulsive or have difficult with impulse control are more likely to be obese and if they perceive sweet, high calorie foods as being more desirable than the general population. Given this, you screen a group of participants and recruit participants (n=20) that have high impulsivity scores (that is, they are more impulsive). From your sample, you collect participant’s weight and scores on the Food Perception Inventory (FPI) which measures individual’s preference for high calorie foods. For obesity, you know the national mean (168) and standard deviation (26.38), but you only know the population mean (103) for the FPI. Using the data below, answer the following questions:

Participant ID	Weight	FPI
1	204	115
2	198	111
3	219	119
4	250	122
5	170	105
6	232	110
7	178	104
8	177	107
9	192	109
10	198	110
11	203	115
12	211	114
13	198	112
14	212	120
15	215	119
16	236	120
17	196	115
18	198	115
19	180	112
20	210	121

Questions:

1. Report the sample mean and standard deviation for both Weight and FPI

2. What is the decision rule (i.e. how will you determine if this sample is unique or rare)?

3. Calculate a one sample test for Weight and Report the result

4. What is your decision for Weight? Interpret your result

Answer 1

1.

	Weight	FPI
mean	203.85	113.75
sample standard deviation	20.40	5.34

2. Reject the null hypothesis if the p-value < 0.05.

3. The results are:

168.000	hypothesized value
203.850	mean Weight
20.402	std. dev.
4.562	std. error
20	n
19	df
7.858	t
2.18E-07	p-value (two-tailed)

4. The p-value is 0.0000.

Since the p-value (0.0000) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we can conclude that µ ≠ 168.