Help! Which of the following is an observational study and which is an experimen

Question

Help! Which of the following is an observational study and which is an experiment:

1)A biologist measures the amount of a bacterium observed in farm eggs, as well as the incidence of stomach infections in the nearest city to determine if there is a statistical relationship between these variables.

2)A veterinarian decides to feed chimpanzees with different types of food and different liquids to measure the effect of feeding on muscle variation.

3)An astronomer follows an asteroid for several years to determine when it would hit the moon

4)An engineer selects 15 prototypes of a diesel car to determine which is the best performance in miles / gallon of diesel

5)An engineer modifies the amount of raw material and the processing speed to determine if the final product achieve a quality standard

6)Chooses a p-value which indicates the evidence against the null hypothesis is extremely weak

a)0.90

b)0.06

c)0.03

d)0.0001

e)-0.0001

7)In minitab, the quantities under the ADJ MS column are distributed type:

a)Fisher

b)Normal

c)T-student

d)Binomial

e)Chisquare

Explanation / Answer

An observational study is the study in which researcher does not assign treatments to any subjects. An experimental study is the study in which researcher assigns treatments to subjects. There are two groups: control group and treatment group.

1)A biologist measures the amount of a bacterium observed in farm eggs, as well as the incidence of stomach infections in the nearest city to determine if there is a statistical relationship between these variables.

Here biologist did not assign treatment to any subject so it is an observational study.

2)A veterinarian decides to feed chimpanzees with different types of food and different liquids to measure the effect of feeding on muscle variation.

Here veterinarian assign treatments (different types of food and liquids) to chimpanzees (subjects) to measure the effect of feeding on muscle variation so it is an experimental study.

3)An astronomer follows an asteroid for several years to determine when it would hit the moon.

Here astronomer did not assign treatment to any subject so it is an observational study.

4)

An engineer selects 15 prototypes of a diesel car to determine which is the best performance in miles / gallon of diesel.

Here engineer did not assign treatment to any subject so it is an observational study.

5)

An engineer modifies the amount of raw material and the processing speed to determine if the final product achieve a quality standard.

Here engineer modifies the amount of raw material and the processing speed so he did an experimat. So it is an experimental study.

6)

The larger the p-value, weaker the the evidence against the null hypothesis.

Correct option: a)0.90

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