Answer:
For , x = 2, or x = - 2.
Step-by-step explanation:
Here, the given expression is :
Now, using the ALGEBRAIC IDENTITY:
Comparing this with the above expression, we get
⇒Either (x-2) = 0 , or ( x + 2) = 0
So, if ( x- 2) = 0 ⇒ x = 2
and if ( x + 2) = 0 ⇒ x = -2
Hence, for , x = 2, or x = - 2.
Answer:
47.06% of the population has an IQ between 85 and 105.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
What percent of the population has an IQ between 85 and 105?
This is the pvalue of Z when X = 105 subtracted by the pvalue of Z when X = 85. So
X = 105
has a pvalue of 0.6293.
X = 85
has a pvalue of 0.1587
So 0.6293 - 0.1587 = 0.4706 = 47.06% of the population has an IQ between 85 and 105.