Question

A)

Suppose that a medical researcher wants to explore whether there is an effect of age in systolic blood pressure for males between 40 to 60 years old. To investigate the relationship, a random sample of 100 males between 40 to 60 years old were selected and their systolic blood pressure was recorded.

Identify each of the following for this experiment.

Subjects: Individuals between 40 to 60 years old Or Males between 40 to 60 years old Or Systolic blood pressure Or Age Or Gender Or Males

Response variable: Individuals between 40 to 60 years old Or Males between 40 to 60 years old Or Systolic blood pressure Or Age Or Gender Or Males

Explanatory variable: Individuals between 40 to 60 years old Or Males between 40 to 60 years old Or Systolic blood pressure Or Age Or Gender Or Males

B)

Which one of the following is not a principle of good experimental design?

Group of answer choices

a)Response bias

b)Double-blind

c)Replication.

d)Randomization

C)

A 95% confidence interval for a population mean is calculated to be (2.5, 3.4). Which is the most suitable statement to interpret this interval from the following?

Group of answer choices

a)95% of the observations lie between 2.5 and 3.4.

b)We are 95% confident that the true population mean lies between 2.5 and 3.4.

c)We are 100% sure that the true population mean lies between 2.5 and 3.4.

d)We are 95% confident that the true population mean lies outside this interval.

Answer 1

A) -

Here, the researcher wants to explore whether there is an effect of age in systolic blood pressure for males between 40 to 60 years old.

So, To investigate this relationship, a random sample of 100 males between 40 to 60 years old were selected. Hence, subjects for this experiment is males between 40 to 60 years old.

We have to check is there any effect of age in systolic blood pressure which means that we have to check that systolic blood pressure is dependent or not on the age, so response variable is systolic blood pressure (dependent variable) & explanatory variable is age (independent variable).

B) -

We know that replication, randomization & double blind are good principles of good experimental design.

Replication - Repeat experiments many times, it reduces variability in experimental results

Randomization - Random assignment of treatments, it minimizes bias response

Double blind - Experimental procedure in which neither the participant nor the experimenter are aware of which group each participant belings to, it prevent bias in research results.

Response bias - The tendancy of the person to answer questions on survey misleadingly, it may signficantly impact the experimental results.

Hence, response bias is not a principle of good experimental design.

C) -

A 95% confidence interval for a population mean is calculated to be (2.5,3.4).

So, the correct statement to interpret interval is B i.e. "we are 95% confident that true population mean lies between 2.5 & 3.4".

Statement a is wrong because it is not about the observations, it is about the population mean.

Statement c is wrong because we are not 100% sure that population mean lie between 2.5 & 3.4. We are just 95% sure.

Statement d is also wrong because confidence interval gives that population mean lies inside interval not outside the interval.

So, option B is correct.