Exam grades: scores on a statistics final in a large class were normally distributed with a mean of 80 and a standard deviation of 9. use the ti-84 plus calculator to answer the following. round the answers to at least four decimal places. (a) what proportion of the scores were above 93? (b) what proportion of the scores were below 64? (c) what is the probability that a randomly chosen score is between 72 and 90?

(a) 0.075

(b) 0.038

(c) 0.677

Step-by-step explanation:

(a) P(Z > 93) = P(Z > )

= 0.075

(b) P(Z < 64) = P(Z < )

= 0.038

(c) P( 72 < Z < 90) = P( -0.89 < Z < 1.11)

⇒ P(1.11 ) - P(-0.89) = 0.677

i dont know men

step-by-step explanation:

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.