Answer:the z score is - 1
Step-by-step explanation:
Assuming a normal distribution for the delivery time of sandwiches by Sammy's Sandwich Shop. We would apply the formula for normal distribution which is expressed as
z = (x - u)/s
Where
x = delivery times
u = mean delivery time
s = standard deviation
From the information given,
u = 25 minutes
s = 2 minutes
We want to determine the z-score for the number of sandwiches delivered in less than 23 minutes. It becomes
z = (23 - 25)/2 = - 1
1/3 of all students bring lunch
2:3 is the ratio of students who bring their lunch to the number of students who do not
60%. You count how many total (15) and then how many got below a 90 (9) and then divide 9 by 15.
