Assume that the mean weight of 1-year-old girls in the USA is normally distributed, with a mean of about 9.5 kilograms and a standard deviation of approximately 1.1 kilograms. Calculate the z-scores in 2 decimal places for each of the following weights in kilograms: 8.4 z - score = Blank 1 7.3 z - score = Blank 2 11.7 Z - score = Blank 3

The time it needs a communications worker to arrange a domestic phone call is normally distributed with mean  Fifty seconds and a standard deviation of  Eight seconds. Find the proportion of times that someone has to wait for more than a minute for the call to be placed.

The length of songs in the Big Hair playlist of a Statistics professor's mp3 player varies from song to song. This variation can be modeled by the normal distribution, with a mean song length of �=4.3 minutes and a standard deviation of �=0.65 minutes. (Note that a song that has a length of 4.5 minutes is a song that lasts for 4 minutes and 30 seconds.)The professor decides to shuffle the playlist, which means that the mp3 player will randomly pick a song within this particular playlist and play it next.(a) What is the probability that the next song to be played is between 3.9 and 4.85 minutes long? Answer to four decimals. (b) What proportion of all the songs in this playlist are longer than 5 minutes? Use four decimals in your answer. (c) 20% of all the songs in this playlist are at most how long, in minutes? Enter your answer to two decimals. minutes(d) There are 247 songs in the Big Hair playlist. How many of these would you expect to be longer than 5 minutes in length? Use two…

To assess the air quality in a surgical suite, the presence of colony-forming spores per cubic meter of air is measured on three successive days. The results are as follows: {12, 24, 30}. Calculate the mean and standard deviation for these data.