(1 point) A random sample of $n$ measurements was selected from a population with unknown mean $\mu$ and standard deviation $\sigma$. Calculate a 90% confidence interval for $\mu$ for each of the following situations:
(a) $n = 10$, $\bar{x} = 4.2$, $s = 2.59$
$\leq \mu \leq$
(b) $n = 17$, $\bar{x} = 6.1$, $s = 4.05$
$\leq \mu \leq$
(c) $n = 19$, $\bar{x} = 23.9$, $s = 3.21$
$\leq \mu \leq$
(d) $n = 14$, $\bar{x} = 82.1$, $s = 3.77$
$\leq \mu \leq$