Question

Probenecid is a drug used by some athletes to prevent the excretion of other substances into urine, thus lowering their detectable concentrations. A scientist makes three measurements of a urine sample known to contain probenecid and obtains a confidence interval of 11.8±0.5 mg/L at the 95% confidence level. What would happen to the confidence interval at the same confidence level if the number of measurements is increased to 10 assuming the standard deviation remains the same?

Answer 1

The confidence interval will decrease

Explanation:

Generally the confidence interval is mathematically represented as

`\= x \pm z_c * (s)/(√(n) )`

Here
`z_c` is called the critical value of
`(level \ of \ significance )/(2)` obtained from the normal distribution table , s is the standard deviation , n is the sample size (number of measurements )

Now looking at the formula we that if the increase the sample size that the confidence level would decrease

So if the n is increased to 10

The confidence interval would decrease