Answer:
a) Expected score on the exam is 12.8.
b) Variance 10.24, Standard deviation 3.2
Step-by-step explanation:
For each question, there are only two possible outcomes. Either you guesses the answer correctly, or you does not. The probability of guessing the answer of a question correctly is independent of other questions. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:

The variance of the binomial distribution is:

The standard deviation of the binomial distribution is:

64 questions.
So 
5 possible answers, one correctly, chosen at random:
So 
(a) What is your expected score on the exam?

(b) Compute the variance and standard deviation of x. Variance =Standard deviation

Variance 10.24

Standard deviation 3.2
Answer:
Volume of water and air is 3,000 mm³
Step-by-step explanation:
Given:
Length of base = 15 mm
Width of base = 20 mm
Height of figure = 30 mm
Find:
Volume of water and air is inside each of the plastic ice cubes.
Computation:
Height of each rectangular pyramid = Height of figure / 2
Height of each rectangular pyramid = 30 / 2
Height of each rectangular pyramid = 15 mm
Volume of each rectangular pyramid = lbh / 3
Volume of each rectangular pyramid = [15 × 20 × 15] / 3
Volume of each rectangular pyramid = [4,500] / 3
Volume of each rectangular pyramid = 1,500 mm³
Volume of water and air is inside each of the plastic ice cubes = 2 × Volume of each rectangular pyramid
Volume of water and air is inside each of the plastic ice cubes = 2 × 1,500
Volume of water and air is inside each of the plastic ice cubes = 3,000 mm³
Answer: a) Unimodal and symmetric
b) 0.26
c) 0.038
Step-by-step explanation:
Given: Sample size of investors (n)= 131
True proportion of smartphone users(p) =26%
a) Since sampling distribution for the sample proportion is approximately normal when n is larger.
Normal distribution is Unimodal and symmetric.
So correct option : Unimodal and symmetric
b) mean of this sampling distribution = p = 0.26
c) standard deviation of the samplingdistribution = 

Slope intercept form is y=mx+b.
Y and x stay.
M is your slope.
B is your y-intercept.
Hope that this helps!
The piecewise function is
f(x) = 2, 0 < x ≤ 1/2
f(x) = 2 + 0.7x, x > 1/2
<h3>How to determine the piecewise function?</h3>
From the question, we have:
Fares = $2.00 ⇒ up to (and including) 1/2 miles
Fares = $0.70 increment ⇒ greater than 1/2 miles
Let x represent the number of miles, and f(x) the fares.
So, we have:
f(x) = 2, 0 < x ≤ 1/2
f(x) = 2 + 0.7x, x > 1/2
The above represents the piecewise function
Read more about piecewise function at:
brainly.com/question/18859540
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