Question

For a set of 1000 observations known to be normally distributed, the mean is 534 cm and standard deviation is 13.5 cm. How many observations are likely to exceed 561 cm ? How many will be between 520.5 cm and 547.5 cm ? (given : p (05 z 51) = 0.3413; p (05 z 2) = 0.4772)

Answer 1

Answer:

Step-by-step explanation:

A)I assume that the "bell-shaped distribution"  

means that the variable,X, is normal with µ=25 and σ=4.  

P(X<33)=  

P(Z<(33-25)/4)=  

P(Z<2)=  

0.9772 (obtained from a cumulative normal chart or calculator)  

=97.72%  

B) There are 1000 observations  

so there will be approximately  

1000×0.9772  

=977 that are less than 33.