contestada

The Mental Development Index (MDI) of the Bayley Scales of Infant Development is a standardized measure used in longitudinal follow-up of high-risk infants. The scores on the MDI have approximately a normal distribution with a mean of 100 and standard deviation of 16. What proportion of children have MDI of at least 80?

Respuesta :

Answer:

0.8944

Step-by-step explanation:

The proportion of children have MDI of at least 80=P(X≥80)

P(X≥80)=P((X-mean)/sd≥(80-100)/16)

We are given that mean=100 and standard deviation=sd=16. So,

P(X≥80)=P(z≥-20/16)

P(X≥80)=P(z≥-1.25)

P(X≥80)=P(-1.25<z<0)+P(0<z<+∞)

P(X≥80)=0.3944+0.5

P(X≥80)=0.8944

Thus, the proportion of children have MDI of at least 80 is 0.8944 or 89.44%

Otras preguntas