Transcript Calculations for the normal distribution on the ti 83/84

AP Statistics
On your own: Scores of each of the previous English tests were
normally distributed with a mean of 76 and standard deviation of
4.5. Kenny will be taking the test tomorrow.
 What is the probability of Kenny getting at least 66
on the test?
Now Lets Try it on our Calculator
 2nd vars
 Select normalcdf
 Type normalcdf(lowerbound, upperbound, mean, standard deviation)
 So, the problem was: Scores of each of the previous English tests were
normally distributed with a mean of 76 and standard deviation of 4.5.
Kenny will be taking the test tomorrow. What is the probability of
Kenny getting at least 66 on the test?
 Type normalcdf(66, 1E99, 76, 4.5)
Scores of each of the previous history tests were normally distributed with a
mean of 76 and standard deviation of 4.3. Ginger will be taking the test
tomorrow. What is the probability of Ginger failing to get between 63 and 74 on
the test?
 Do this by hand.
Now, lets do it on the calculator
 Scores of each of the previous history tests were
normally distributed with a mean of 76 and standard
deviation of 4.3. Ginger will be taking the test
tomorrow. What is the probability of Ginger failing to
get between 63 and 74 on the test?
 Type 2nd vars
 Select normalcdf(
 Normalcdf(lowerbound, upperbound, mean, standard
deviation)
 normalcdf(63, 74, 76, 4.3)
Scores of each of the previous history tests were normally
distributed with a mean of 84 and standard deviation of 1.8.
Sharon will be taking the test tomorrow. What is the probability of
Sharon getting at most 87 on the test?
 Do this by hand
Now, lets do it on the calculator
 Scores of each of the previous history tests were
normally distributed with a mean of 84 and standard
deviation of 1.8. Sharon will be taking the test
tomorrow. What is the probability of Sharon getting at
most 87 on the test?
 2nd vars
 Select normalcdf(
 Normalcdf(lowerbound, upperbound, mean, standard
deviation)
 Normalcdf(-1E99, 87, 84, 1.8)
What about using the table
backwards?
 Inversenorm
 Use invnorm(area, mean, standard deviation)
Scores of each of the previous calculus tests were normally distributed with a
mean of 86 and standard deviation of 2.2. How high must a student’s score be
to score in the top 20%?
 Do this by hand
Now its calculator time!
 Scores of each of the previous calculus tests were
normally distributed with a mean of 86 and
standard deviation of 2.2. How high must a
student’s score be to score in the top 20%?
 2nd vars
 Invnorm(area to the left, mean, standard
deviation)
 invnorm(.8, 86, 2.2)