Question

1) Of all the trees planted by a landscaping firm, 10% survive. What is the probability that 7 or more of the 9 trees they just planted will survive? (Use a table of binomial probabilities. Give your answer correct to four decimal places.)

2)

Find the following probabilities for X = pulse rates of group of people, for which the mean is 78 and the standard deviation is 4. Assume a normal distribution. (Round all answers to four decimal places.)

(a) P(X ≤ 75).


(b) P(X ≥ 84).


(c) P(68 ≤ X ≤ 86).

Answer 1

1) Given

Percentage of trees survived= 10% = 0.1 (probability of success)

Sample size, n = 9

Probability that 7 or more of the 9 trees they just planted will survive ,

                      

From cumulative binomial distribution table, we can compute P(X<7) ,

So,

Probability that 7 or more of the 9 trees they just planted will survive is 0.