Final answer:
The new confidence intervals and sample size when changing confidence level and sample size.
Step-by-step explanation:
a) The new confidence interval would be (0.422, 0.578)
b) The new confidence interval would be (0.439, 0.560)
c) The new confidence interval would be (0.389, 0.611)
d) The new sample size would have to be 480 to make the margin of error half as big in the 98% confidence interval.