sampled $101$ students and calculated an average of $6\mathrm{.}5$ hours of sleep each night with a standard deviation of $2\mathrm{.}14.$ Using a $90\%$ confidence level, she also found that t$*=1\mathrm{.}660.$

c o n f i d e n c e space i n t e r v a l space equals space x with bar on top plus$-$or$-$minus t asterisk times space bevelled fraction numerator s over denominator square root of n end fraction

A $90\%$ confidence interval calculates that the average number of hours of sleep for working college students is between $\_\_\_\_\_\_\_\_\_\_$ hours. Answer choices are rounded to the hundredths place.

a$.)$

$6\mathrm{.}15$ and $6\mathrm{.}85$

b$.)$

$6\mathrm{.}08$ and $6\mathrm{.}92$

c$.)$

$6\mathrm{.}46$ and $6\mathrm{.}85$

d$.)$

$6\mathrm{.}46$ and $6\mathrm{.}54$