An accelerated life test on a large number of type-d alkaline batteries revealed that the mean life for a particular use before they failed is 19.0 hours. the distribution of the lives approximated a normal distribution. the standard deviation of the distribution was 1.2 hours. about 95% of the batteries failed between what two values?

Step-by-step explanation:

Let X be the accelerated life test on a large number of type-D alkaline batteries revealed that the mean life for a particular use before they failed

X is NOrmal with mean =19, sigma = 1.2

For 95% critical value = ±1.96

Margin of error = ±1.96*1.2

=±2.352

Confidence interval 95% = Mean ±2.352

=(16.648, 21.352)

step-by-step explanation:

always plug in x. in this case, x equals 4.

i'm going to first solve 4(2+3x)

1) 4(2+3(4)) use pemdas to solve.

i'm going to multiply whats in the parenthesis first, so 3 times 4=12.

2)4 (2+12) i'm then going to multiply 4 by both numbers in the parenthesis (because multiplying comes before adding)

4 times 2= 8.   4 times 12= 48

4) (8+48)= 56 (answer)

i'm then going to solve 8+12x and plug in 4 for x.

1) 8 +12(4)

multiplying comes before adding, so i'm gonna multiply 12 and 4.

12 times 4= 48.

2) 8+48=56

both equal the same!