The number of practice hours per week for Maranda's piano recital is 13 hours
Overall practice hours = 52 hours
Number of weeks of practice = 4 weeks
Since, the number of practice hours per week is the same ;
Number of hours practiced each week can be obtained by dividing the overall practice hours by the number of weeks of practice.
Number of practice hours per week = Overall practice hours ÷ Number of weeks of practice
Number of practice hours = (52 ÷ 4) = 13 hours
Therefore, Marana practiced for 13 hours each week.
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I like to do it by adding 4 and 3 to get 7. then divide 35 by 7. that would be 5. take 5*4 to get 20 boys and 5*3 to get 15 girls.
Answer:
The confidence interval is from 69.82 o 82.18
Step-by-step explanation:
Using this formula X ± Z (s/√n)
Where
X = 76 --------------------------Mean
S = Standard Deviation
If Variance = 144
S = √144
S = 12
n = 25 ----------------------------------Number of observation
Z = 2.576 ------------------------------The chosen Z-value from the confidence table below
Confidence Interval || Z
80%. || 1.282
85% || 1.440
90%. || 1.645
95%. || 1.960
99%. || 2.576
99.5%. || 2.807
99.9%. || 3.291
Substituting these values in the formula
Confidence Interval (CI) = 76 ± 2.576 (12/√25)
CI = 76 ± 2.576(12/5)
CI = 76 ± 2.576(2.4)
CI = 76 ± 6.1824
CI = 76 + 6.1824 ~ 76 - 6.1824
CI = 82.1824 ~ 69.8176
CI = 82.18 ~ 69.82
In other words the confidence interval is from 69.8176 to 82.1824
Answer:
Step-by-step explanation:
