Hi I need help please

15%

Step-by-step explanation:

Percent Error formula is the difference between the Actual and the guess value    divided by the actual.

So it's 198- 172  /  172  x 100

= 15%

a. 0.9049

b. 0.2297

c. 0.8473

Step-by-step explanation:

Given U = 46.7, SD = 1.75

and Z = (U - X)/sd

(a). We want to find P(X<=49)

P(X<=49) = P(Z<= 49-46.7/1.75)

= P(Z<= 1.31)

= 0.90490

~= 0.9049

(b) P(X>=48) = P(Z>=48-46.7/1.75)

=P(Z>=0.7429) = 1 - P(Z<=0.7429)

= 1 - 0.77035

= 0.22965

=0.2297

(c) The required probability is given by P(U±2.5).

P(46.7±2.5) = (44.2<= X <=49.2)

= P( 44.2<= Z <= 49.2)

= P(44.2 - 46.7/1.75 <= Z <= 49.2- 46.7/1.75)

= P( - 1.4286 <= Z <= 1.4285)

= P(1.4285) - P(-1.4285)

= P(1.43 ) - P(-1.43)

= 0.92364 - 0.07636

= 0.8473