Hi guys for part (c), Im not sure what to use for the standard deviation in the t-test, any help greatly appreciated

A vegetable producer is interested in the evolution of weekly sales on a particular product over

the past 6 months. Historical data indicated an average weekly sales per retailer of 2,400 units

of the product, over the past 6 months. Following a change in the advertising strategy for this

product, a random sample of sales from 134 dierent retailers was gathered and an average

weekly sale of 3,593 units per retailer was calculated. Consider that the aim of this study is to

assess whether the weekly sales of the product have signicantly increased.

(a) State whether you would carry out a one-sided or a two-sided test.

(b) State the null and alternative hypotheses.

(c) Compute the value of the t-test statistic.

(d) Explain whether you would accept the null hypothesis and why