In a recent study on world happiness, participants were asked to evaluate their current lives on a scale from 0 to 10, where 0 represents the worst possible life and 10 represents the best possible life. The responses were normally distributed, with a mean of

Complete Question

The complete question is shown on the first uploaded image  

a

b

c

d

The correct option is  B

Step-by-step explanation:

From the question we are told that

  The mean is  

  The standard deviation is

Generally the  probability that a randomly selected study participant's response was less than 4 is mathematically represented as

So

From the z-table  

So

Generally the probability that a randomly selected study participant's response was between 4 and 6 is mathematically represented as

=>

=>  

=>  

From the z-table  

So  

=>      

=>      

Generally the  probability that a randomly selected study participant's response was more than 8 is mathematically represented as

From the z-table  

So

-13

step-by-step explanation:

f(x)=2x-5 for f(-4)

f(-4)   means let x=-4

f(-4) = 2(-4) -5

f(-4) =-8-5

      = -13

example 2 – simplify: step 1: completely factor both the numerators and denominators of all fractions. step 2: change the division sign to a multiplication sign and flip (or reciprocate) the fraction after the division sign; essential you need to multiply by the reciprocal. step 3 : cancel or reduce the fractions.