Complete the chart to find the mean, variance and standard deviation. remember to use commas and round numbers to the nearest tenth.

To find the mean of the data set, we will simply take the average of the data as:

                              Mean= 345+340+400+625/ 4

                                                   = 427.5

So we have mean as, 427.5

Now we have to calculate the variance of the data.

As we know, for variance we take the difference of each value from mean, take its square and then average of all.

Now

                            Variance=σ2 =(-82.5)^2 + (-87.5)^2 + (-27.5)^2+ (197.5)^2 /4  

                              σ2=6806.25+7656.25+756.25+39006.25/4

                                                           σ2=13556.25

So, the variance is 13556.2

Now we have to calculate the Standard deviation (S.D) of the data.

And the Standard Deviation is just the square root of Variance, so:

                                                  σ=√13556.25

                                                      σ=116.43

So, the S.D of the data is 116.4

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.