Compute a 95% confidence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments. Use the unpooled standard error and use the smaller of n1 - 1 and n2 - 1 as a conservative estimate of degrees of freedom. (Round the answers to one decimal place.)
To compute a 95% confidence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments, we can follow these steps:
Step 1: Calculate the sample means and sample standard deviations for both groups.
Step 2: Calculate the unpooled standard error using the formula:
SE = √((s1^2 / n1) + (s2^2 / n2))
where s1 and s2 are the sample standard deviations of the placebo and zinc lozenge groups, and n1 and n2 are the sample sizes of the two groups.
Step 3: Determine the degrees of freedom (df) to be used in the t-distribution. Use the smaller of n1 - 1 and n2 - 1 as a conservative estimate of degrees of freedom.
Step 4: Find the t-value for a 95% confidence interval with the calculated degrees of freedom.
Step 5: Calculate the margin of error by multiplying the t-value with the calculated standard error.
Step 6: Construct the confidence interval by subtracting and adding the margin of error to the difference in sample means.
Now let's go through the steps with the given information:
Step 1: We need the sample means and sample standard deviations of both groups. Unfortunately, this information is not provided, so we cannot proceed with the calculations.
To compute the confidence interval, you will need the sample means and standard deviations for both the placebo and zinc lozenge groups. Once you have those values, you can follow the remaining steps to calculate the confidence interval.