Noise levels at 4 volcanoes were measured in decibels yielding the following data: 153,156,168,138 Construct the 99% confidence interval for the mean noise level at such locations. Assume the population is approximately normal. Step 1 of 4 : Calculate the sample mean for the given sample data. Round your answer to one decimal place.

153.8 dB

Step-by-step explanation:

The mean required in the firat step is calculated by dividing the sum of individual records by their frequency

Where n is frequency

In this case, since we are provided with four different records, their their sum will be given by

Sum x= 153+156+168+138=615 dB

Therefore, the mean will be

Rounding off to 1 decimal point, then the mean is approximately 153.8 dB

his chances of getting a coin of higher value is 4/19

step-by-step explanation:

step-by-step explanation:

if you want to solve percent error follow these steps.

1. subtract the accepted value from the experimental value.

2. take the absolute value of step 1.

3. divide that answer by the accepted value.

4. multiply that answer by 100 and add the % symbol to express the answer as a percentage.

if you want to solve percent of change just do this.

1. work out the difference (increase) between the two numbers you are comparing.

2. divide the increase by the original number and multiply the answer by 100. if your answer is a negative number then this is a percentage decrease.

hope this : )