Question 916211
Re TY
Ho mean = 120
Ha mean ≠  120
two- tailed testing as written above: .05 on either side</u>
Sample: mean = 123.7625 and s = .293247
The assignment called for the t-test: t = (x-bar-120)/(s/&#8730;n)
Critical value is then ± 1.685,  invT(.05,49)& invT(.95, 49)
.....
As to  desired t(sample mean)= 81.147  = 3.7625/.0463664 = 81.147
Obtaining that exact number to the thousandths place... will depend on decimal points used along the way..
Important, is that  t(123.7625) so far exceeds the critical value,  Ho is rejected.
Wish You the Best in your Studies. 
1. Always important to know number of decimal points that are expected for the desired answer  as to: (x-bar-120)/(s/&#8730;n) for ex 
2. Does the exercise call for the t-test 
If Population SD is unknown, t-test is recommended.
3. The Ho and Ha as written above calls for a two tailed. 
That is t(123.76)= 81.147 was to be compared to critical t-value 1.635