Answer:
Yes
Explanation:
Yes, there is the presence of a threat.
This threat is known as instrumentation. There is an Instrumentation threat when changes are made in the instrument, or the changes are made in the researcher, or the scorer when the research is being carried out.
In this question, mrs smith is the one who is the researcher, the program of reinforcement can be called the instrument. She made errors during the first few week but started getting it right in the second week. So there is a slight change in these two weeks. Causing instrumentation threat to how valid the program is.
Guatemala is a constitutional democratic Republic divided into 22 departments and governed by 3 branch systems ( executive, legislative, and judicial)
Answer: The confidence interval would be (82198.71, 103801.28).
Explanation:
Since we have given that
Mean = $93,000
Standard deviation = $17,000
n = 12 < 30
So, we will use 't-test' to find the 95% confidence interval,
Here , 
and 
So, according to t table, we get that

So, interval would be

Hence, the confidence interval would be (82198.71, 103801.28).