Advertisements
Advertisements
प्रश्न
People’s monthly electric bills in Chennai are normally distributed with a mean of ₹ 225 and a standard deviation of ₹ 55. Those people spend a lot of time online. In a group of 500 customers, how many would we expect to have a bill that is ₹ 100 or less?
Advertisements
उत्तर
Let X be a normally distributed variable with a mean of ₹ 225 and a standard deviation of ₹ 55
Here µ = 225 and σ = 55
The standard normal variate z = `(x - mu)/sigma = (x - 225)/55`
P(a bill have ₹ 100 or less) = P(X ≤ 100)
When x = 100
z = `(100 - 25)/55`
= `(-125)/55`
= – 2.27
P(X ≤ 100) = P(Z < – 2.27)
P(z < – 2.27) = P(`-oo` < z < 0) – P(– 2.27 < z < 0)
= 0.5 – P(0 < z < 2.27)
= 0.5 – 04884
= 0.0116
APPEARS IN
संबंधित प्रश्न
Out of 750 families with 4 children each, how many families would be expected to have atmost 2 girls
Forty percent of business travellers carry a laptop. In a sample of 15 business travelers, what is the probability that 3 will have a laptop?
The mean of a binomial distribution is 5 and standard deviation is 2. Determine the distribution
Determine the binomial distribution for which the mean is 4 and variance 3. Also find P(X=15)
Consider five mice from the same litter, all suffering from Vitamin A deficiency. They are fed a certain dose of carrots. The positive reaction means recovery from the disease. Assume that the probability of recovery is 0.73. What is the probability that atleast 3 of the 5 mice recover
Define Poisson distribution
It is given that 5% of the electric bulbs manufactured by a company are defective. Using poisson distribution find the probability that a sample of 120 bulbs will contain no defective bulb
Write down any five chief characteristics of Normal probability curve
The time taken to assemble a car in a certain plant is a random variable having a normal distribution of 20 hours and a standard deviation of 2 hours. What is the probability that a car can be assembled at this plant in a period of time. Less than 19.5 hours?
The annual salaries of employees in a large company are approximately normally distributed with a mean of $50,000 and a standard deviation of $20,000. What percent of people earn between $45,000 and $65,000?
