# Assume that the mean weight of 1 year-old girls

Question

3. Assume that the mean weight of 1 year-old girls in the US is normally distributed with a mean of about 9 . 5 grams with a standard deviation of approximately 1 . 1 grams. Without using a calculator, estimate the percentage of 1 year-old girls in the US that www.ck12.org 250 meet the following conditions. Draw a sketch and shade the proper region for each problem. (a) Less than 8 . 4 kg (b) Between 7 . 3 kg and 11 . 7 kg (c) More than 12 . 8 kg

4. For a standard normal distribution, placethefollowinginorderfromsmallesttolargest. (a) The percentage of data below 1 (b) The percentage of data below ? 1 (c) The mean (d) The standard deviation (e) The percentage of data above 2

5. The 2007 AP Statistics examination scores were not normally distributed, with ? = 2 . 80 and ? = 1 . 34 1 . What is the approximate z ? score that corresponds to an exam score of 5 (The scores range from 1 ? 5 ). (a) 0 . 786 (b) 1 . 46 (c) 1 . 64 (d) 2 . 20 (e) A z ? score can not be calculated because the distribution is not normal.

6. The heights of 5 th grade boys in the United States is approximately normally dis- tributed with a mean height of 143 . 5 cm and a standard deviation of about 7 . 1 cm. What is the probability that a randomly chosen 5 th grade boy would be taller than 157 . 7 cm?

7. A statistics class bought some sprinkle (or jimmies) doughnuts for a treat and noticed that the number of sprinkles seemed to vary from doughnut to doughnut. So, they counted the sprinkles on each doughnut. Here are the results: 241 , 282 , 258 , 224 , 133 , 335 , 322 , 323 , 354 , 194 , 332 , 274 , 233 , 147 , 213 , 262 , 227 , 366 (a) Create a histogram, dot plot, or box plot for this data. Comment on the shape, center and spread of the distribution. (b) Find the mean and standard deviation of the distribution of sprinkles. Complete the following chart by standardizing all the values

How do I go about answering these quesions? Thanks in advance ðŸ™‚