Suppose a random sample of size 49is drawn from a population with a mean value of 278. If the probability that a sample mean is less than 280equals 0.67, what is the standard deviation of the population

Standard deviation of the population = 31.82

Step-by-step explanation:

We are given that a random sample of size 49 is drawn from a population with a mean value of 278 i.e.;

Population mean, = 278   and    Sample size, n = 49

The z probability value is given by, Z = ~ N(0,1)

Also, we are given the probability that a sample mean is less than 280 equals 0.67 i.e.;

              P( < 280) = 0.67

              P( < ) = 0.67

              P(Z < ) = 0.67

Now, looking at z table we find that the probability area of 0.67 is given at the critical value of x of 0.44 which means;

                     ⇒   = 0.44

                     ⇒ = 14/0.44 = 31.818 ≈ 31.82.

Therefore, the standard deviation of the population, = 31.82 .

in the math equation 8 x 7 = 56, the 8 and the 7 are both factors of 56, since in this lesson we will use square tiles to figure out the factors of a whole find as many different arrays as you can, but follow one important rule: all the rows must have the i can make two rows of nine, so 2 and 9 are both factors of 18.

step-by-step explanation:

b: |12 – x| ≤ 0.25

step-by-step explanation:      

let x be the possible lengths in inches, of the ribbons jaime cut.

we have been given that jaime is cutting strips of ribbon for a project. he tries to cut each piece to be 12 inches long, but sometimes he cuts it too long or too short by as much as 0.25 inch.  

we can represent this information in an inequality as:

by the definition of absolute value function we will get,

upon combining our inequalities we will get,

therefore, the inequality   describes all the possible lengths (x), in inches, of the ribbons jaime cut.

step-by-step explanation: