Answer:
25
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 175cm
Standard deviation = 6 cm
Percentage of students below 163 cm
163 = 175 - 2*6
So 163 is two standard deviations below the mean.
By the Empirical rule, 95% of the heights are within 2 standard deviations of the mean. The other 100-95 = 5% are more than 2 standard deviations of the mean. Since the normal distribution is symmetric, 2.5% of them are more than 2 standard deviations below the mean(so below 163cm) and 2.5% are more than two standard deviations above the mean.
2.5% of the students have heights less than 163cm.
Out of 1000
0.025*1000 = 25
25 is the answer
Answer:
(-3,2)
Step-by-step explanation:
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This are the right steps
Step 1: first you divide the both size by 7 because there is 7 a's
7a/7 = 28/7
Step 2: You solve the equation
7a/7= a. 28/7 = 4
So, the answer is a = 4
not 7 = 4
Do it in ratio form, 30/10=x/4, 30*4=120/10=12. it will be 12 centimeters long