Answer:
41/60
Step-by-step explanation:
Convert the fractions into like denominators: 7/30 = 140/600, 9/20 = 270/600
Add: 140/600+270/600 = 410/600
Divide into a smaller fraction: 41/60
Let's calculate the z scores for 42 and 58:
42 - 50
z = ------------- = -1
8
58-50
z = --------------- = 1
8
so the question becomes: what percent of the data should fall within 1 std. dev. of the mean? Referring to the empirical formula: 68% (answer)
Answer:
the last one
Step-by-step explanation:
because you have two (-1) and that means it is not a function.
Answer:
(228.663 ; 241.337)
Step-by-step explanation:
Given that:
Mean (m) = 235
Standard deviation (s) = 28
α = 95%
Zcritical at 95% = 1.96
Sample size (n) = 75
The confidence interval of the population mean can be obtained using the relation :
Mean ± Error
Error = Zcritical * (s/sqrt(n))
Error = 1.96 * (28/sqrt(75))
Error = 1.96 * 3.2331615
Error = 6.33699654
Error = 6.337
Lower boundary = 235 - 6.337 = 228.663
Upper boundary = 235 + 6.337 = 241.337
(228.663 ; 241.337)
