Infer. statistics in Decision making

1. The researcher in this case, conducts an analysis of the relationship between cardiovascular disease and type II diabetes. The results of this analysis is comprehensively summarized in the succeeding table.

Patient	BMI (kg/m2)	Hypertension (Y/N)	Diabetes Type II (Y/N)	Smoking status (Never, Quit, Social, Current)	Education Status (<High, High, >High)	Alcohol (>2 drinks a day? Y/N)	Religious Background (Catholic, Jewish, Muslim, Other)	Ethnicity (AA, W, A, H, Other)
A	27	N	N	Current	<High	Y	Catholic	AA
B	34	Y	Y	Never	>High	Y	Other	A
C	21	N	N	Quit	High	Y	Other	W
D	28	Y	N	Social	>High	N	Muslim	W
E	36	Y	Y	Current	<High	Y	Jewish	W

A) Describe the following in reference to their status as a variable, observation, or value:

B) Are any of the variables included in the study ordinal? If so, identify the ordinal variables.

2.

What can we say about the device with regards to its precision, accuracy, and potential bias?

Measurement	Boiling Point (degrees Fahrenheit)
1	129
2	137
3	136
4	141
5	139
6	142
7	136
8	127
9	143
10	123

3.

The researcher is experimenting on the measurement ability of a new device intended to read the freezing point of a chemical compound. The substance used in the investigation has a known freezing point of -24 degrees Celsius. In the investigation, it was required that the researcher should conduct a series of 10 sample measurements of the freezing point, and then tabulate the results.

What can we say about the device with regards to its precision, and potential bias?

Measurement	Freezing Point (degrees Celsius)
1	-26
2	-18
3	-32
4	-31
5	-24
6	-24
7	-24
8	-24
9	-11
10	-37

3.

A researcher is investigating a new screening tool that is intended to help prevent the onset of breast cancer in young women. This researcher tests the new device on a group of 10 women. The acquired results have been tabulated besides the true breast cancer statuses of the screen women.

What can we say about the new device with regards to its accuracy?

Patient	Test Result	True Cancer Status
A	+	+
B	+	+
C	+	-
D	+	-
E	-	+
F	-	+
G	+	-
H	-	+
I	-	-
J	+	-

4.

A surveyor decides to sample students randomly from a classroom in order to get information about teacher satisfaction. There are 29 students in the class, and the surveyor has randomly assigned each of the students a number. The surveyor wishes to randomly select 10 students using the following number table.

741928 657381 104823 571628 021598 204878 123596 897635 234807 646079 659735

A) What kind of sample is this? Simple random sampling.

B) What assumptions must be made about the population in order to continue with the sampling design?

C) Assuming the above assumptions do hold, what are the numbers corresponding to the 10 students in the sample that would be selected from the classroom?

5.

. A surveyor is determined to sample homeowners in south Philadelphia before the next local election in order to assess key issues that people want to see changes for this year. Suppose the surveyor decides that he will first collect a list of eligible voters from the county, and separate that list into four groups based on annual income. Then, the surveyor randomly assigns each household a number 01-10 within each group of income. The surveyor will select 4 households from each income group using the following random number table. Once 4 households are selected for one group, the surveyor would continue with the next on the same line of the table.

081203 071072 058436 080695 010354 080951 213607 041573 083947 101503 785409

A) What kind of sampling strategy is this? Cluster sampling

B) Which households would be selected for each income group from this table?

6.

A surveyor wants to sample a city for the local Public Health Office in order to assess asthma rates annually. In order to get the best estimate for the project, the surveyor first decides to sample 2 of 15 census tracts, and then to sample 5 households from each tract. Assume there are only 10 households in each tract. The surveyor randomly assigns each tract in the city a number 01-15, and each household in each tract a number 01-10. Use the following random number table to select each tract, and then each household, continuing along the line.

058791 211403 098746 170528 086401 370614 097810 036418 340514

A) What kind of sampling strategy is this? Stratified sampling.

B) Which census tracts and households will be selected?