The duration of routine operations at chicago general hospital has approximately a normal distribution with an average of 130 minutes and a standard deviation of 12 minutes. what proportion of operations last at least 120 minutes

The following division is being performed using multiplication by the reciprocal find the missing numbers is 5/12 divided by x/3 equals 5/12 times x/10 equals 1/x

A, at (-2, 4), is 6 .of a'? (-8, 4) (-8, -2) (-2, -2) (-2, 4) b, at (-4, -7), isy-.of b'? (-4, 7) (4, -7) (4, 7) (-4, -7)

Use the given degree of confidence and sample data to construct a confidence interval for the population mean mu . assume that the population has a normal distribution. a laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 185 milligrams with sequals 17.6 milligrams. a confidence interval of 173.8 mgless than muless than 196.2 mg is constructed for the true mean cholesterol content of all such eggs. it was assumed that the population has a normal distribution. what confidence level does this interval represent?