Question

If the probability of selecting a bolt from $400$ bolts is $0.1$, then the mean for the distribution is ________

• A. $0.09$
• B. $40$
• C. $36$
• D. $360$

Answer 1

The correct option is B $40$

${\mu }_x=np$

where ${\mu }_x$ is mean of x

$n=$ sample size

$p=$ probability of success on an individual trial

Here

$n=400$

$p=0.1$

${\mu }_x=np=400\times 0.1=40$