Groceries In January 2011, Yahoo surveyed 2400 U.S. men. 1224 of the men identified themselves as the primary grocery shopper in their household. a) Estimate the percentage of all American males who identify themselves as the primary grocery shopper. Use a 98% confidence interval. Check the conditions first. b) A grocery store owner believed that only 45% of men are the primary grocery shopper for their family, and targets his advertising accordingly. He wishes to conduct a hypothesis test to see if the fraction is in fact higher than 45%. What does your confidence interval indicate? Explain. c) What is the level of significance of this test? Explain.

STAT 2004 CHAPTER ONE: WEEK 4 SAMPLE STATISTICS n 2 1 2 Sample variance- s = n−1 i=1x ix´) Sample standard deviation- Tells you how spread out your data is. It is the square root of the variance. QUANTILES Also known as percentiles. o If you are in the 70 percentile, you are better than 70% of your class and not as good as 30%. DISTRIBUTION Describes shape, center, and spread/variation of data. For the images below, imagine histograms that fit the depicted curves. BOXPLOT A boxplot uses a five number summary consisting of the median (Q ), 2