.
Evaluation:
the heights of 200 plants in a garden follow a normal distribution with a mean of 72.3 cm
with a SD of 8.9 cm.
1. about how many plants whose heights are between 82 and 90 cm?
~~~~~~~~~~~~~~~~
You can use your regular calculator TI-84, standard function normalcdf
(normal cumulative distribution function). It gives the area under the normal curve between
the assigned scores, showing you the desired part of 200 plants
z1 z2 mean SD <<<---=== formatting pattern
P = normalcdf(82, 90, 72.3, 8.9) = 0.1145.
So, approximately 0.1145 of 200 plants are in this range, or 0.1145*200, which is about 23 plants.
Alternatively, you can use this online free of charge calculator
https://onlinestatbook.com/2/calculators/normal_dist.html
Solved and explained.