Work out a) 1 1/5 + 3 2/5
1 answer:
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Answer: 0.7258
Step-by-step explanation:
Given : A telemarketer makes a sale on 25% of his calls.
i.e. p=0.25
He makes 300 calls in a night, i.e. n=300
Let x be a random variable that represents the number of calls make in night.
To convert the given binomial distribution to normal distribution we have :-
Now, using , the z-value corresponds to x= 70 :-
The z-value corresponds to x= 90 :-
By using the standard normal distribution table for z, the probability that he will make more than 70 sales but less than 90 sales:-
Hence, the probability that he will make more than 70 sales but less than 90 sales= 0.7258