Question

The amount of dollars an American spends in a month on groceries is normally distributed with a mean of $300 and a standard deviation of $20. Using the standard deviation rule, approximately what percentage of spend between $240 and $360? O A 68% B. 95% 99.7% OD. 50%

Answer 1

TOPIC:Empirical rule and Categorical variable.

The answer is @ 99.7%. = Explanation a we know, Normal distribution is bell- shaped. Then, by the Empirical Rule; when, MI mean, o=sd; we have, - 68% of the data falls within (M-o, uto); in 95%. " " " " " (M-20, me +20) and ging 99.7%. " which is also known as standard deviation rule Here M=$300. and s= $ 20. and the given a interval is - ($ 240, $360. - (4300 - 3 * $20, $300 + 3x $ 20). = (-30, M+30). rule- So, by- lily ; we get, Required percentage ] 99.7 %. OLAM, Required percentage = 99.7 7.1

a question. 4x The → answers are Zip code Income year in schools. 3) Explanation - In the given data, - years. - age is collected in teate = year in school is collected as a ( Freshman , sophomore, Juniors, 0 senion. x income is collected as a < $5,000 per year, I 5,000 $15,000 per year 74 • 15,000 per year.

codes =) are in collected the and the zip usual way Observe that only the age of the students is a quantitative continuous variable, as it can be expressed numetiee ty numerically and it is eligible don significant numerical & mathematical operations, On the other hand, year in school is collected as four categories. Incomes come are collected as three categories and the zip codes are also categorical, as they are just an indicator of particular places and are measured in Nominal level of measurement. Hence, the categorical variables - are - Zip code, income, Year in school of CAnd