Answer: Our required probability is 0.65.
Step-by-step explanation:
Since we have given that
18-20 Not 18-20 Total
Male 0.23 0.35 0.58
Female 0.16 0.26 0.42
Total 0.39 0.61 1
P(female or between 18-20) = P(female) + P(18-20) - P(Female and 18-20)
P(female or between 18-20) = 0.42+0.39-0.16
P(female or between 18-20) = 0.65
Hence, our required probability is 0.65.
Answer:
There is no significant difference between the means.
Step-by-step explanation:
Given is the data set for X1 and x2 are we have to do a paired t test.

(Two tailed test at 5% significance level)
Mean difference = 1.00
Std error for difference = 1.225
df=4
Test statistic = mean diff/se = 1.826
p value =0.142
Since p >0.05 our alpha we accept H0
There is no significant difference before and after averages at 5% sign. level.
Answer: 
Step-by-step explanation:
You know that the total time was: 7/8 hour
You also know that they spent 1/2 of the time at the beach.
Therefore, to calculate the time Zach and his dog spend at the beach (which you can call x) , you must multiply both fractions (7/8 and 1/2).
Then, you obtain the following result:

Answer: b. 0.8413
Step-by-step explanation:
Given : The average time taken to complete an exam, X, follows a normal probability distribution with
and
.
Then, the probability that a randomly chosen student will take more than 30 minutes to complete the exam will be :-
[using z-value table]
Hence, the probability that a randomly chosen student will take more than 30 minutes to complete the exam = 0.8413