Answer: Mean = 5.25
Variance = 1.3125
Standard deviation = 1.456
Step-by-step explanation:
The mean and variance of a binomial distribution with parameters n (number of trials) and p ( the probability of getting success in each trial) is given by :-
[tex]\text{Mean}=np\\\\\text{Variance}=np(1-p)[/tex]
Given : The total number of enter a clothing store : n=7
The probability of a customer making a purchase= 0.75
Now,
[tex]\text{Mean}=7(0.75)=5.25\\\\\text{Variance}=7(0.75)(0.25)=1.3125\\\\\Rightarrow\ \text{Standard deviation}=\sqrt{1.3125}=1.14564392374\approx1.1456[/tex]