Answer:
Sample size should be atleast 617
Step-by-step explanation:
given that a 95% confidence interval for the mean of a population is to be constructed and must be accurate to within 0.3 unit.
i.e. margin of error <0.3
Std devition sample = 3.8
For 95% assuming sample size large we can use z critical value
Z critical = 1.96
we have

Sample size should be atleast 617 to get an accurate margin of error 0.3
Answer:
40
Step-by-step explanation:
n/10+5=9
n/10=9-5
n/10=4
n=4*10
n=40
Product is multiplication.
Let the number = x
3 *( X+7) = -36
Use distributive property:
3x +21 = -36
Subtract 21 from each side:
3x = -57
Divide both sides by 3:
x = -57 /3
x = -19
Check: 3 * (-19 +7) = 3 * -12 = -36
The number is -19
Could you attach photo of a problem. It appears 2+..... =4 is missing