I got C for 6 & 7. I haven't done this in a while so I don't know 8 & 9. I hope I helped!
Answer:
x=2
Step-by-step explanation:
Answer:
P(Male = 2) = 63.9%
Step-by-step explanation:
40000C2 / 50000C2
[(40000 * 39999) / (1*2)] / [(50000 * 49999 *) / (1*2)]
3,199,920,000 / 4,999,900,000
0.6399996799935999
P(Male = 2) = 63.9%
Answer:
A certain company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a battery is normally distributed, with a mean of 50 months and a standard deviation of 9 months. If the company does not want to make refunds for more than 10% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries?
The company should guarantee the batteries for 38 months.
Step-by-step explanation:
Using standard normal table,
P(Z < z) = 10%
=(Z < z) = 0.10
= P(Z <- 1.28 ) = 0.10
z = -1.28
Using z-score formula
x = zσ + μ
x = -1.28 *9+50
x = 38
Therefore, the company should guarantee the batteries for 38 months.
