Answer:
The critical value of <em>t</em> at 0.01 level of significance is 2.66.
Step-by-step explanation:
The hypothesis for the two-tailed population mean can be defined as:
<em>H₀</em>: <em>μ </em>= <em>μ₀</em> vs. <em>H₀</em>: <em>μ </em>≠ <em>μ₀</em>
It is provided that the population standard deviation is not known.
Since there is no information about the population standard deviation, we will use a <em>t</em>-test for single mean.
The test statistic is defined as follows:

The information given is:
<em>n</em> = 55
<em>α</em> =<em> </em>0.01
Compute the critical value of <em>t</em> as follows:

*Use a <em>t</em>-table for the value.
If the desired degrees of freedom are not provided consider he next highest degree of freedom.
Thus, the critical value of <em>t</em> at 0.01 level of significance is 2.66.
Answer:
http://eldata2.neu.topica.vn/TXTOKT02/Giao%20trinh/03_NEU_TXTOKT02_Bai2_v1.0014109205.pdf
Step-by-step explanation:
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Answer:
a = 0 or a = -7
Step-by-step explanation:
We are going to solve this quadratic equation by factorizing.
a² - 7a = 0
a(a - 7) = 0
a = 0 or a - 7 = 0
a = 0 or a = -7