Question

Use technology or a z-score table to answer the question.

Answer 1

Answer with explanation:

We have to find , P (z< 1.45).

 Breaking ,z value into two parts, that is , In the column,the value at, 1.40 and in the row ,value at , 0.05,the point where these two value coincide,gives value of Z<1.45.

The value lies in the right of mean.

So, P(z<1.45)=0.9265

In the,Normal curve, at the mid point of the curve

Mean =Median =Mode

Z value at Mean = 0.5000

→So, if you consider , the whole curve,

P(Z<1.45)= 0.9265 × 100=92.65%=92%(approx) because we don't have to consider ,z=1.45.

→But, if you consider, the curve from mean ,that is from mid of the normal curve

P (z<1.45)=92.65% - 50 %

           =42.65% =42 %(approx) because we don't have to consider ,z=1.45.

Answer 2

P(z < 1.45) ≈ 0.92647

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On the TI-83/84 calculator, the normalcdf( ) function requires a lower bound. The area of the normal curve below z=-8 is less than 10^-11, so -8 is a suitable stand-in for -∞. All the decimal digits shown are accurate, not affected by our choice of lower bound.