Consider the following probability distribution function of the random variable X which represents the number of people in a group (party) at a restaurant: X P(X) 1 0.10 2 0.25 3 0.20 4 0.20 5 0.10 6 7 0.05 8 0.05 a. Find the population mean of X. b. Find the population variance and standard deviation of X. c. Find the probability that the next party will be over 4 people. d. Find the probability that the next three parties (assuming independence) will each be over 4 people.

(a) 3.55

(b) 3.45 and 1.86

(c) 0.25

(d) 0.016

Step-by-step explanation:

The random variable X denotes the number of people in a group (party) at a restaurant.

(a)

The formula to compute the mean is:

Consider the Excel sheet attached.

The mean is, 3.55.

(b)

The formula to compute the variance is:

Consider the Excel sheet attached.

Compute the variance as follows:

The variance is, 3.45.

Compute the standard deviation as follows:

The standard deviation is, 1.86.

(c)

Compute the probability that the next party will be over 4 people as follows:

Thus, the probability that the next party will be over 4 people is 0.25.

(d)

Compute the probability that the next three parties will each be over 4 people as follows:

It is provided that the three parties are independent.

P (Next 3 parties will be each over 4) = [P (X > 4)]³

Thus, the probability that the next three parties will each be over 4 people is 0.016.

something that characterises a right triangle is the fact that we may use pythagoras' theorem to find any one of its sides given that we have the length of the other two sides. here, we have the length of the hypotenuse, √(87) yd, and one other side, √(23) yd, thus we can easily find the length of the remaining side using pythagoras' theorem as defined below:

c^2 = a^2 + b^2, where c is the length of the hypotenuse, and a and b are the lengths of the other two sides.

thus, given that c = √(87) and a = √(23), we may substitute these into the formula we defined above to get:

c^2 = a^2 + b^2

(√87)^2 = (√23)^2 + b^2 (substitute c = √87 and a = √23 into the equation)

87 = 23 + b^2 (evaluate (√87)^2 = 87 and (√23)^2 = 23 - remember that the square root of a number, squared will equal that very same number)

64 = b^2 (subtract 23 from both sides)

√64 = b (take the square root of both sides)

8 = b (evaluate √64 = 8)

therefor, the length of the unknown leg in the right triangle is 8 yd (first answer).