B17.este in poza va rog ajutor rapid

The force acting on a beam was measured under the same operating conditions and a sample of 5 data points was collected. this process was repeated by 3 observers. the pooled standard deviations of these 3 data sets was 1.21. determine the true mean force using all pooled data (with a 95% probability). the result should look like this: true mean = mean +/- margin of error

Could someone . i have tried to solve myself but my calculation is off

Which body part transports oxygen removes waste materials in carries nutrients to the body as part of the circulatory system