find area of indicated region under the standard normal curve
the numbers are -.45 and 2.11 its shaded more towards the right i got the answer .3438 why is it not 1-normalcdf (-.45, 2.11, 0, 1) and why is it just normalcdf(-.45,2.11,0,1)
http://davidmlane.com/hyperstat/z_table.html
Yeah yeah
To find the area of the indicated region under the standard normal curve, you can use the cumulative distribution function (CDF) of the standard normal distribution.
The function normalcdf(a, b, μ, σ) calculates the area under the normal curve between the z-scores a and b, where μ represents the mean of the distribution and σ represents the standard deviation.
In this case, since you are working with the standard normal distribution (mean = 0 and standard deviation = 1), you can simply use the function normalcdf(a, b).
Therefore, the correct calculation would be normalcdf(-.45, 2.11).
The reason you don't subtract the result from 1 is that the CDF already calculates the area to the left of the given z-score. So, you don't need to perform the 1-normalcdf(-.45, 2.11, 0, 1) calculation.
To find the area of the indicated region under the standard normal curve, you can use the cumulative distribution function (CDF) of the standard normal distribution. The CDF function, typically denoted as Φ(z), gives you the probability that a standard normal random variable is less than or equal to a given value.
In this case, you need to find the area under the standard normal curve from -.45 to 2.11. Since this region is shaded more towards the right, you want to calculate the probability of being to the left of -.45 and subtract it from the probability of being to the left of 2.11.
The reason you only need to use `normcdf(-.45, 2.11, 0, 1)` rather than `1 - normcdf(-.45, 2.11, 0, 1)` is because `normcdf` already gives you the cumulative probability to the left of the specified upper bound. It calculates the area under the curve up to that point. So, `normcdf(2.11, 0, 1)` gives you the probability of being to the left of 2.11.
To understand why you don't subtract the probability of being to the right of -.45 from 1, consider that the cumulative distribution function measures the probability to the left of a value. So, when you use `normcdf(-.45, 0, 1)`, you are already calculating the probability of being to the left of -.45.
In summary, to find the area of the indicated region under the standard normal curve, you can use `normcdf(-.45, 2.11, 0, 1)`, which gives you the probability to the left of 2.11 and subtracts the probability to the left of -.45, giving you the desired area.