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The birth weights for two groups of babies were compared in a study. In one group...

The birth weights for two groups of babies were compared in a study. In one group the mothers took a zinc supplement during pregnancy. In another group, the mothers took a placebo. A sample of 98 babies in the zinc group had a mean birth weight of 3423 grams. A sample of 80 babies in the placebo group had a mean birth weight of 3004 grams. Assume that the population standard deviation for the zinc group is 686 grams, while the population standard deviation for the placebo group is 783 grams. Determine the 98% confidence interval for the true difference between the mean birth weights for "zinc" babies versus "placebo" babies.

Step 1 of 2:

Find the critical value that should be used in constructing the confidence interval.

Step 2 of 2:

Construct the 98%confidence interval. Round your answers to the nearest whole number.

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