One of the assumptions underlying the theory of control charting is that successive plotted points are independent of one another. Each plotted point can signal either that a manufacturing process is operating correctly or that there is some sort of malfunction. Even when a process is running correctly, there is a small probability that a particular point will signal a problem with the process. Suppose that this probability is 0.05. What is the probability that at least one of 10 successive points indicates a problem when in fact the process is operating correctly? What is the probability that at least one of 40 successive points indicates a problem when in fact the process is operating correctly?

a) the probability that at least one of 10 successive points indicates a problem when in fact the process is operating correctly is 0.4013

b) the probability that at least one of 40 successive points indicates a problem when in fact the process is operating correctly is 0.8715

Step-by-step explanation:

following how the independence multiplication rule works,

i.e finding p(A)' which is 1 - p(No problem) because what we need is an intersection not a union so;

a) 10 successive points

probability (problem) = 0.05

probability (No problem) = 0.95

required probability = 1 - [probability (No problem)]^10

= 1 - (0.95)^10

= 1 - 0.5987

= 0.4013

the probability that at least one of 10 successive points indicates a problem when in fact the process is operating correctly is 0.4013

b) 40 successive points

probability (problem) = 0.05

probability (No problem) = 0.95

required probability = 1 - [probability (No problem)]^40

= 1 - (0.95)^40

= 1 - 0.1285

= 0.8715

the probability that at least one of 40 successive points indicates a problem when in fact the process is operating correctly is 0.8715

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt