In a study of 205 adults, the mean heart rate was 75 beats per minute. assume the population of heart rates is known to be approximately normal with a standard deviation of 8 beats per minute. what is the 95% confidence interval for the mean beats per minute?

answer:

(74.8905,75.1095)

step-by-step explanation:

given that in a study of 205 adults, the mean heart rate was 75 beats per minute.

sigma = population std deiation = 8

std error = 8/sqrt 205

=8/14.32

=0.559

margin of error = z crit *std error

z critical for 95% = 1.96

margin of error = 1.96(0.559)

=1.095

conf interval lower bound = mean -margin of error

=75-0.1095

=74.8905

upper bound = 75+0.1095 = 75.1095

1) c 2143.6 cm

2) c 113.0 m

3) a 33.5 ft

4)   d 2 cm

5) c 20 mm

6) 180 in

7) d 120 ft