Answer:
(a) 0.85
(b) 0.7225
Step-by-step explanation:
(a) The point estimate for the proportion of all such components that are not defective is given by the number of non-defective units in the sample divided by the sample size:

The proportion is 0.85.
(b) Assuming that the sample is large enough to accurately provide a point estimate for the whole population, this can be treated as a binomial model with probability of success (non-defective part) p = 0.85. Since both components must be non-defective for the system to work, the probability of two successes in two trials is:

An estimate of 0.7225 for the proportion of all such systems that will function properly.
Answer: 6
Explanation:
x + 2x + 1 + 5x + 4 = 53
8x + 5 = 53
8x = 48
x = 6
Answer: C.) 1.12 seconds
Step-by-step explanation:
Hi, to answer this question we have to substitute h=0 (when the rock hits the ground the height above it is 0) in the equation given:
h (t) = –16t2 + 20
Solving for t (time)
0= –16t2 + 20
16t2=20
t2=20/16
t=√1.25 =1.12 seconds (option C)
Feel free to ask for more if needed or if you did not understand something.