Posted by Anonymous on .
how to know exact t value using sample standard deviation and sample mean and sample size
i think df is sample size 1 .
we usually use approx value but to use exact value how to use t score table.
and how we conclude whether it is two tailed test or one tailed test .
(i f the problem asks for exact increase or decrease ,is it one tailed test ,i guess so ,)
please clarify my doubts

statistics t test 
PsyDAG,
Yes, df = n1
For twotailed test:
Ho: mean = X
Ha: mean ≠ X
For onetailed test:
Ho: mean < or = X
Ha: mean > X
or
Ho: mean > or = X
Ha: mean < X
Ho = null hypothesis
Ha = alternative hypothesis 
statistics t test 
Anonymous,
how do we know it is one tailed test or two tailed test?

statistics t test 
PsyDAG,
What are your hypotheses? That determines difference between onetailed and twotailed (see my previous post).

statistics t test immediate help needed 
Anonymous,
the average weekly earnings of a production worker were $424. to know if wages, on average, have gone up since that time. To test this, you sample 64 production workers, and determine that their average salary is $432.69, with a sample standard deviation of $33.90. Use a 0.05 level of significance .carry out test .
is it t test or z test ? how would we know
in this case one tailed or two tailed how can we know? 
statistics t test 
rosie,
If a population proportion is 0.29 and if the sample size is 120, 25% of the time the sample proportion will be less than what value if you are taking random samples?
Round your answer to 2 decimal places, the tolerance is +/0.01.