 # If 80% of the applicants are able to pass a driver's proficiency road test, how do you find the mean, variance, and standard deviation of the number of people who pass the test in a sample of 300 applicants? Tarnayfu 2022-08-09 Answered
If 80% of the applicants are able to pass a driver's proficiency road test, how do you find the mean, variance, and standard deviation of the number of people who pass the test in a sample of 300 applicants?
You can still ask an expert for help

• Live experts 24/7
• Questions are typically answered in as fast as 30 minutes
• Personalized clear answers

Solve your problem for the price of one coffee

• Math expert for every subject
• Pay only if we can solve it neglegir86
Expected value of X, $Mean=\mu =np=300\ast 0.8=240$
Mean is: $\mu =240$
Variance: ${\sigma }^{2}=np\left(1-p\right)=300\ast \left(0.8\right)\left(1-0.8\right)=48$
Variance: ${\sigma }^{2}=48$
Std Dev: $\sigma =\sqrt{{\sigma }^{2}}=\sqrt{48}\approx 6.928203\approx 6.928$
Standard deviation: $\sigma =6.928$

We have step-by-step solutions for your answer!