business statics
posted by kenneth .
a random sample of the grade of 78 students is taken. what is the probability that the average grade will be between 80.3% and 82.3%?

Need a measure of central tendency (mean) and a measure of variability (standard deviation).
Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z scores.
Respond to this Question
Similar Questions

Math  average grade
Does anyone know how to calculate average point grade? 
statistics
1. The oncampus housing costs for a semester at a state university are Normally distributed with a mean of $1553 and a standard deviation of $329. (a) What is the distribution of the mean oncampus housing cost for a semester at this … 
Probability Math
A committee of four students will be selected from a list that contains six Grade 9 students and eight Grade 10 students. What is the expected number of Grade 10 students on the committee? 
Math
Approximately 15% of the students in ST130 obtain A grade. If 3 students are selected at random, find the probability that a)all of them obtain A grade in ST130. b)Exactly 2 obtain A grade in ST130. c)at least one obtain A grade in … 
Statistics
The average grade point average(GPA)of undergraduate students in New York is normally distributed with a population mean of and a population standard deviation of. Compute the following, 1)The percentage of students with GPA'S between … 
Statistics
`The average grade point average (GPA) of undergraduate students in New York is normally distributed with a population mean of 2.5 and a population standard deviation of 0.4. Compute the following, showing all work: 1) The percentage … 
Business Stats
The average life expectancy of Canadian women is 75 years, and is normally distributed. The standard deviation is known to be 7 years. If a random sample od 49 women is taken, what is the probability that the average age of the sample … 
Statistics
2.5 Points 30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation … 
Math HELP!!!!!
30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. … 
Math HELP!!!!!
30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. …