These histograms graph the amount of time (hours per day) that 46 middle school girls and 40 middle school boys in san francisco spend on the website facespace. 50 boys and 50 girls took the survey but 4 girls and 10 boys did not use these sites at all. each is graphed with a bar width of 0.25 hours.

how many boys spent between 0.5 hour and 0.75 hour on the site?

6
8
9
10

d. 24+-0.114

step-by-step explanation:

the question requires us to calculate the approximate 95% confidence interval for the mean number of ounces of ketchup per bottle in the sample given the following statistics;

sample mean = 24

standard deviation, σ = 0.4

sample size , n = 49

the confidence interval for a population mean is calculated using the formula;

sample mean ± z-score*(σ/sqrt(n))

the z-score associated with a 95% confidence interval, from the standard normal tables, is;

1.96

substituting these values into the formula;

24 ± 1.96*(0.4/7)

= 24 ± 0.112

from the alternatives given, choice d is closest to the above expression;

80

step-by-step explanation: