Let z denote a random variable that has a standard normal distribution. Determine each of the probabilities below. (You may need to use a table. Round your answers to four decimal places.) (a) P(Z < 2.38) 0.9913 (b) P(Z ≤ 2.38) 0.9913 USE SALT (c) P(Z <-1.21) 0.1123 X (d) P(1.12

Use excel to do all calculations. Please show all work.

You land a job at an online marketing/consulting firm after attaining a business degree with an emphasis in statistics. You walk into your office on the first day and there is an assignment sitting upon your desk. The firm was recently hired by ImpulseBuy Now.com (a famous online clearing house for as-seen-on-TV junk items). ImpulseBuyNow wanted to know if the amount of time spent browsing by a customer at their online site associates to how many items the customer purchased. Sound familiar? Realizing that you listed a statistical emphasis in your business degree, you panic and pull out your old statistics notes as to find this unit in the study guide. What luck! You must figure out what to tell ImpulseBuy Now about their question. Here is the data provided by ImpulseBuy Now: Browse Time (min.) 0-10 11-20 More than 20 Browse Time (min.) 0-10 Items Purchased Zero 1000 And your final p-value is extremely small. 1500 500 One 900 Expected Values Zero 600 2600 2500 Your paycheck depends…

The scores of a test for an engineering class of 30 students are shown here. (Due to the nature of this problem, do not use rounded intermediate values in your calculations-including answers submitted in WebAssign.) Scores: 81, 54, 55, 56, 96, 86, 98, 61, 90, 52, 92, 76, 66, 84, 79, 70, 71, 88, 62, 74, 53, 65, 55, 78, 79, 58, 60, 72, 51,80 (a) Determine the frequency (f), midpoint (x), and xf for each range and fill in the table below. (First, organize the scores into the following ranges: 50-59, 60-69, 70-79, 80-89, and 90-99.) (b) Using the following equation, determine the mean value (x) and fill in the table below. Σ(XA) n X = (c) Calculate (x − x) for each range and fill in the table below. (d) Calculate (x - x)²f for each range and fill in the table below. Range Frequency f Midpoint x 50-59 60-69 70-79 80-89 90-99 S = Enter a number. S = (e) Using the following equation, compute the standard deviation of the class scores. Σ(x-x) ²f n - 1 Σ(x-x) ²4 n - 1 = xf 29 X X - X (x - x)²f